Madhyamik Class 10 Life Science Solved Paper 2019

Madhyamik Life Science 2019
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Madhyamik Class 10 Life Science Solved Paper 2019

LIFE SCIENCE

Time: 3 Hours and 15 Minutes

(First 15 Minutes for reading the question paper only, 3 Hours for writing) 

Full Marks: For Regular Candidates – 90

For External Candidates – 100

Regular candidates will answer questions from Groups A, B, C and D. External candidates will answer questions from Group E.

(Special Instructions for visually handicapped candidates)

Answer Question 4.1(A) instead of Question 4.1 in Group D. Instruction on how many questions from a group must be attempted is provided at the beginning of the group.

Group ‘A’
(All questions are compulsory)

1. Choose the correct answer for each question and write it with its respective-serial number: [1 × 15=15]

Question 1.1

Select which of the following statement is correctly related to tropic movement –

  1. It is controlled by the intensity of the stimulus
  2. The overall change of place takes place by a plant or part of the plant
  3. This movement is observed in the algae called Vol-vox.
  4. It is an induced movement of curvature controlled by the direction of the stimulus

Answer

It is an induced movement of curvature controlled by the direction of the stimulus

Question 1.2

Read the following sentences and identify the sentence which is not correct –

  1. FSH, LH and Prolactin are different types of GTH
  2. Adrenaline decreases cardiac output
  3. Insulin facilitates the absorption of glucose into the cell through the cell membrane
  4. Progesterone helps in the formation of the placenta in the female body

Answer

Adrenaline decreases cardiac output

Question 1.3

Determine the number of Cranial nerves in the human body –

  1. 10 Pairs
  2. 31 Pairs
  3. 12 pairs
  4. 21 pairs

Answer

12 pairs

Question 1.4

Identify the correct feature of Amitosis cell division –

  1. Occurs in germ mother cell of sexually reproducing organism
  2. It is called indirect cell division
  3. Chromosome and Spindle fibre are formed
  4. Chromosome and Spindle fibre are not formed

Answer

Chromosome and Spindle fibre are not formed

Question 1.5

Determine which of the following statement is correct regarding the significance of meiosis

  1. It results in overall growth and development of body
  2. It results in the growth of reproductive organs and embryo of the organism
  3. It produces haploid gamete containing hereditary variations
  4. It regenerates the organ in the body of some animals if it is lost

Answer

It produces haploid gamete containing hereditary variations

Question 1.6

Select the correct pair and write it –

  1. Multiple fission – Hydra
  2. Fragmentation – Spirogyra
  3. Regeneration – Fern
  4. Budding – Planaria

Answer

Fragmentation – Spirogyra

Question 1.7

Identify which of the following is a dominant trait –

  1. Length of the stem – Dwarf
  2. Shape of the seed – Wrinkled
  3. Colour of the cotyledon – Yellow
  4. Colour of the flower – White

Answer

Colour of the cotyledon – Yellow

Question 1.8

Assess how many types of gametes are produced from the Pea plant having the genotype RRYY –

  1. One type
  2. Four types
  3. Two types
  4. Three types

Answer

One type

Question 1.9

Select which of the following two genotypes are responsible for the expression of the phenotype wrinkled yellow in Pea plants –

  1. RRYY and rryy
  2. RRYy and RrYy
  3. RRyy and Rryy
  4. rrYY and rrYy

Answer

RRyy and Rryy

Question 1.10

Identify which of the following indicates inter-specific struggle –

  1. Struggle among the members of guppy fish for feeding on mosquito larvae
  2. I Struggle between snakes and owls for capturing rats for eating
  3. Struggle within a group of deer for feeding on grass at the same location
  4. Struggle between tigers in a jungle for preying on deer

Answer

I Struggle between snakes and owls for capturing rats for eating

Question 1.11

Determine the term related to the theory of Lamarck –

  1. Struggle for existence
  2. Origin of variation
  3. Inheritance of acquired characters
  4. Natural selection

Answer

Inheritance of acquired characters

Question 1.12

Identify the animal that communicates information with other members of its own group through specific dancing patterns regarding the sources of food –

  1. Chimpanzee
  2. Cockroach
  3. Peacock
  4. Honeybee

Answer

Honeybee

Question 1.13

Decide which of the following remains for a long time in the environment, the probability of its biomagnification increases –

  1. Newspaper
  2. Faecal matters of animals
  3. Rotten leaves
  4. Chlorinated insecticide

Answer

Chlorinated insecticide

Question 1.14

Gorumara, Corbett, Kulik, Nandadevi – choose the correct sequence from the following which is correct for the above forests in sequence –

  1. Biosphere Reserve, Sanctuary, National Park, National Park
  2. National Park, National Park, Biosphere Reserve, Sanctuary
  3. National Park, National Park, Sanctuary, Biosphere Reserve
  4. Sanctuary, Biosphere Reserve, National Park, Sanctuary

Answer

National Park, National Park, Sanctuary, Biosphere Reserve

Question 1.15

If the number of pollen grains, fungal spores, and dust particles increases suddenly in the air, decide which of the following problems may increase –

  1. Tuberculosis
  2. Asthma
  3. Malaria
  4. Dengue

Answer

Asthma

Group – B

2. Answer 21 questions out of 26 questions given below as instructed: [1×21=21]

Question 2.1 – 2.6

Fill in the blanks (any five) [1 × 5=5]

  1. By the influence of  ____ hormone the hairs on the skin get erected an emergency situations.
  2. A chromosome is the condensed coiled structure of ____ molecule.
  3. The sexual reproduction that occurs among two genotypically different organisms belonging to the same species, is called ____.
  4. ____ was the aggregate of some large colloidal molecules during the early phase of the origin of life.
  5. ____ is derived from the root of the Sarpagandha plant which is used as medicine for lowering high blood pressure.
  6. The ex-situ conservation by keeping sample seeds in liquid nitrogen at a temperature of -196°C is called ____.

Answer

  1. Adrenaline
  2. DNA
  3. Hybridisation / conjugation
  4. Concervate
  5. Reserpine
  6. Cryopreservation

Question 2.2 – 2.6

Decide whether the following statements are true or false (any five) : [1 × 5=5]

  1. Dilute urine is profusely eliminated by a person affected with Diabetes Insipidus.
  2. The Carpel of flowering plants collect pollen grains with the help of hairy and sticky style.
  3. A pair of sex-determining sex chromosomes are present in the ovum of humans.
  4. According to Darwin organisms reproduce at geometric ratio. 
  5. One-horned rhinoceros is conserved at Manas National Park of West Bengal. False
  6. Acetylcholine and adrenaline are neurotransmitters. True

Answer

  1. True
  2. False. The carpel of a flowering plant is made up of three parts: the stigma, the style, and the ovary. The stigma is the sticky part that collects pollen grains. The style is the long, thin part that connects the stigma to the ovary. The ovary is where the seeds develop.
  3. False. The ovum of a human only contains one sex chromosome, which can be either an X chromosome or a Y chromosome. The sex of the baby is determined by the sperm, which can contain either an X chromosome or a Y chromosome.
  4. True
  5. False. The one-horned rhinoceros is conserved at Kaziranga National Park in Assam, India.
  6. True

Question 2.3

Match the words in column-A with the most appropriate words in column B and re-write the correct pair mentioning the serial no. of both columns (any five):-  [1 × 5=5]

Column A Column B
1. Presbyopia a) BbRr
2. Cell Differentiation Phase of Growth b) Haldane
3. Genotype of Guinea-pig having black and coarse hair c) Near vision is defective
4. Hot Dilute Soup d) Change of climate and global warming
5. Destruction of forests and erosion of the ecosystem e) Formation of spindle fibre during animal cell division
6. Centrosome f) Formation of tissue, organ and system
g) bbrr

Answer

1 – (c). 2 – (f). 3 – (e), 4 – (b), 5 – (d), 6 – (e)

Question 2.4

Answer in a single word or in a single sentence (any six) [1 × 6=6]

  1. Chose the odd one and write it– Glossopharyngeal, Oculomotor, Trigeminal, Oxytocin
  2. What is the function of the fluid present in the intermediate chamber between lens and retina of the eyeball?
  3. A pair of related terms is given below. On the basis of the relationship in the first pair write the suitable Word in the gap of the second pair.
    Grafting: Mango: ____: China Rose
  4. What is the cause of expression of haemophilia disease only at homozygous conditions?
  5. Write the genotypic ratio obtained at 2nd filial generation in the monohybrid experiment done by Mendel?
  6. Which type of evolution is indicated by homologous organs?
  7. Among the following four terms one includes the other three. Find it out and write it: Pesticides used in Agriculture, Typhoid, Water Pollution, liquid wastes from factories?
  8. In which type of in situ conservation practice, the diversity, culture, and lifestyle of humans are preserved along with microorganisms, wild animals, and wild plants?

Answer

  1. The odd one out is oxytocin. The other three are cranial nerves, while oxytocin is a hormone.
  2. Acts as Refactory medium or maintain pressure or, maintain the shape of the eyeball.
  3. Grafting : Mango : : Cutting: China Rose.
  4. It is caused due to a recessive gene.
  5. 1 : 2 : 1.
  6. Divergent evolution.
  7. Water Pollution.
  8. Biosphere Reserve.

Group – C

3. Answer any 12 questions in 2-3 sentences out of 17 questions given below:

Question 3.1

Illustrate with the help of a word diagram the nervous pathway of the way you will open the door by hearing the doorbell.

Answer

Stimuli(sound of the doorbell)
↓
Receptor(the spiral organ of corti)
↓
Sensory neurone (Optic nerve)
↓
Nerve Center (Brain)
↓
Motor neurone (Cranial nerve)
↓
Effector (The hand will move up by muscles contraction)
↓
Response (open the door)

Question 3.2

State the locations of Meninges and CSF.

Answer

  1. The Meninges are three protective membrane layers surrounding the Brain and spinal cord.
  2. CSF occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord.

Question 3.3

What influences does the gibberellin hormone exert on the seeds and internode of plants? Explain.

Answer

Gibberellins break dormancy in seeds and produce an elongation of the stem by increasing the length of the internodes.

Question 3.4

Write the names of the different refractive mediums of eyeballs in proper sequence.

Answer

The different refractive mediums of the eyeball are:

Aqueous chamber (Aqueous humour) → Lens → Vitreous Humour.

Question 3.5

During the meiosis cell division, a reduction in the number of chromosomes and exchange of segments between chromatids take place Analyse what is the significance of these two phenomena.

Answer

During Meiosis cell division, the significance of the following two phenomena are:

  1. Reduction in the number of chromosomes: The chromatids of each chromosome get separated. Therefore, in meiosis, the final product gets half the number of chromosomes of the mother cell. This led to the formation of gametes.
  2. Exchange of segment between chromatid: Exchange in the segment between two chromatids give birth to new variations in the offspring.

Question 3.6

Distinguish between asexual and sexual reproduction on the basis of the following features:

  1. Number of Parents
  2. Nature of offspring

Answer

Feature Asexual Sexual
Number of patents Only one parent is required. Two parents are required.
Nature of offspring The offspring are genetically identical to the parent. The offspring are not genetically identical to the parents.

 

Question 3.7

Identify the stages of Karyokinesis of mitotic cell division depending on the following features:

  1. Alignment of chromosomes along the equator of the cell and their arrangement in a definite pattern
  2. The disintegration of spindle fibres
  3. The disappearance of nuclear membrane and nucleolus
  4. Movement of daughter chromosomes to the opposite poles of the cell

Answer

  1. Metaphase
  2. Anaphase
  3. Prophase
  4. Anaphase

Question 3.8

To establish the law of segregation in case of Pea plants, you are asked to select characters. Write two such characters having opposite traits.

Answer

Here are two characters having opposite traits that Mendel selected to establish the law of segregation in pea plants:

  • Flower colour: Purple and white
  • Seed shape: Round and wrinkled

Question 3.9

A daughter is born to a woman carrier for the colour-blind disease who married a colour-blind man. What would be the probability of expression of colour blindness in that girl child? Analyse your answer.

Answer

X°X – Carrier woman.

X°Y – Colour blind man.

Result – 50% of daughters colour blind

50% daughter carrier.

Conclusion – The born female baby may be colourblind or carrier possibly – 50% checkerboard.

probability of expression of colour blindness

Question 3.10

Write the name of two genetic diseases which are expressed in human populations.

Answer

Colour blindness and Haemophilia are the two genetic diseases expressed in the human population.

Question 3.11

Tigers are extinct but there are many deer in the jungle. A few tigers are brought from another sanctuary and released in such a jungle. Imagine and write the names of different kinds of struggle for existence those tigers have to be involved in.

Answer

Interspecific and Intraspecific struggle.

Question 3.12

Describe any two adaptations in the Sundari plant for tolerance of salt.

Answer

The following are the two adaptations in the Sundari plant for tolerance of salt:

  1. Sundari plants possess succulent leaves and stem.
  2. They possess thick-walled cutinized epidermis with hairy covering.

Question 3.13

Explain how the chimpanzees hunt termites for food.

Answer

Chimpanzees are quite clever and can prepare a tool with a small tree branch. After defoliating the tip of the twig, it is crushed to prepare it like a brush. Then the brush is inserted into the termite mound. This stick-like brush is then pulled out when quite a good number of termites may be collected for eating.

Question 3.14

List the harmful effects of the following pollutants

  1. Greenhouse gas
  2. SPM
  3. Chemical fertilizers used in agriculture
  4. Non-biodegradable chemical insecticide

Answer

  1. Greenhouse gas: Greenhouse gases trap heat in the atmosphere, which can cause global warming. This can lead to a number of problems, including rising sea levels, more extreme weather events, and changes in agricultural yields.
  2. SPM: Suspended particulate matter (SPM) is a mixture of solid particles and liquid droplets that are suspended in the air. SPM can be harmful to human health, causing respiratory problems such as asthma and bronchitis. It can also damage plants and ecosystems.
  3. Chemical fertilizers used in agriculture: Chemical fertilizers can pollute waterways and groundwater, leading to eutrophication and other problems. They can also contribute to the formation of smog and acid rain.
  4. Non-biodegradable chemical insecticide: Non-biodegradable chemical insecticides can persist in the environment for long periods of time. This can lead to the accumulation of these chemicals in the food chain, which can have harmful effects on human health and wildlife.

Question 3.15

Give one example of exotic species causing damage to local biodiversities in each terrestrial and aquatic ecosystem.

Answer

(i) European gipsy math, (ii) European starting

(i) Zebra Musscle (ii) Chinese Mittuch crab

Question 3.16

Write the in-situ conservation measures taken for one endangered reptile species and name one site of such conservation in West Bengal.

Answer

The crocodile reserve project was started.

The Bhagabatpur crocodile reserve project is situated in West Bengal to conserve crocodiles.

Question 3.17

“Poaching is one of the fundamental causes of endangeredness of animal diversity in India” Assess four causes for which animals are poached in India.

Answer

(i) Food (ii) Skin (iii) Horns (iv) Ivory etc

Group – D

[Long Answer Type Questions]

4. Write six questions or their alternatives given below. Sightless candidates have to answer question No. 4.1 (A) instead of 4.1: – [5×6=30]

Question 4.1

Draw a neat diagram of a neurone and label the following parts : [3+2=5]

  1. Dendron
  2. Node of Ranvier
  3. Myelin sheath
  4. Schwann cell

Answer

neurone

OR

Draw a neat diagram of the anaphase of mitosis of an animal cell and label the following parts : [3+2=5]

  1. Polar region
  2. Spindle
  3. Chromatid
  4. Centromere

Answer

 

[For Sightless Candidates Only]

Question 4.1 (A)

Write one function of each of the following five parts of a neurone: – [1×5=5]

  1. Dendron
  2. Cell body
  3. Axon
  4. Myelin sheath
  5. Schwann

Answer

  1. Dendrites: Receive electrical signals from other neurons.
  2. Cell body: Contains the nucleus and other organelles.
  3. Axon: Transmits electrical signals to other neurons.
  4. Myelin sheath: Insulates the axon and speeds up the signal transmission.
  5. Schwann cells: Produce the myelin sheath.

OR

Mention three changes that occur in the anaphase stage of mitosis in animal cells. Write the name of any two structural parts of the eukaryotic chromosome. [3+2=5]

Answer

Here are three changes that occur in the anaphase stage of mitosis in animal cells:

  1. The sister chromatids separate and move to opposite poles of the cell. This is caused by the breakdown of the cohesin proteins that hold the sister chromatids together.
  2. The spindle fibres shorten, pulling the chromosomes apart. This is caused by the activity of the motor proteins on the spindle fibres.
  3. The nuclear envelope reforms around each set of chromosomes. This is caused by the assembly of new nuclear membranes around the chromosomes.

Here are the names of two structural parts of the eukaryotic chromosome:

  1. Centromere: The centromere is the region of the chromosome where the sister chromatids are attached.
  2. Telomere: The telomere is the end of the chromosome. It is a repetitive sequence of DNA that protects the chromosome from damage.

Question 4.2

Why reproduction is important for an organism? “Meiosis is characteristically different from Mitosis” – how would you justify the statement ? [2+3=5]

Answer

Here are some reasons why reproduction is important for an organism:

  1. Reproduction ensures the continuity of the species
  2. Reproduction allows for genetic variation
  3. Reproduction can be a source of pleasure

Meiosis is characteristically different from mitosis in the following ways:

  1. Meiosis produces haploid cells, while mitosis produces diploid cells.
  2. Meiosis involves two rounds of cell division, while mitosis only involves one round.
  3. Meiosis is involved in sexual reproduction, while mitosis is involved in asexual reproduction.

OR

Describe five processes of asexual reproduction with one suitable example for each. [5]

Answer

Here are five processes of asexual reproduction with one suitable example for each:

  1. Binary fission: A single cell divides into two identical cells. This is the most common form of asexual reproduction and is found in bacteria, amoebas, and many other organisms. [Example: E. coli bacteria reproduce by binary fission.]
  2. Budding: A small outgrowth, or bud, develops on the parent cell and eventually separates to form a new organism. This type of reproduction is found in yeast, hydras, and some plants. [Example: Yeast reproduce by budding.]
  3. Fragmentation: The parent organism breaks into multiple pieces, each of which can develop into a new organism. This type of reproduction is found in many marine organisms, such as sea stars and planarians. [Example: Planarians reproduce by fragmentation.]
  4. Spore formation: The parent organism produces spores, which are small, reproductive units that can develop into new organisms. This type of reproduction is found in fungi, algae, and some plants. [Example: Molds reproduce by spore formation.]
  5. Vegetative propagation: New plants are produced from parts of the parent plant, such as stems, leaves, or roots. This type of reproduction is found in many plants, such as strawberries, potatoes, and cacti. [Example: Strawberries reproduce by vegetative propagation.]

Question 4.3

Show the result of hybridization till F2 generation between a pure black (BB) coarse-haired (RR) guinea pig and a pure white (bb) smooth-haired (rr) guinea pig by a checkerboard. State the conclusion one can reach from this hybridization experiment. [3+2=5]

Answer

BBRR – pure black, coarse-haired

bbrr – pure white, smooth-haired

Code:

  • BB – pure black
  • RR – coarse-haired
  • bb – pure white
  • rr – smooth haired

Dihybrid cross-

BBRR (1) pure black pure coarse-haired.

BBRr (2) pure black hybrid coarse-haired.

BbRR (2) hybrid black hybrid coarse-haired

BbRr (4) hybrid black hybrid coarse-haired

BBRR (2) hybrid black pure smooth-haired.

bbRR (1) pure white pure coarse-haired.

bbRr (2) pure white hybrid coarse-haired.

bbrr (1) Pure white pure smooth haired.

BBrr (1) pure black pure smooth haired.

Genotype-1:2:12:4:2:1:2:1

Phenotype-9:3:3:1

OR

What symptoms are expressed in a child affected with Thalassaemia? What suggestions are given at the time of genetic counselling in such cases? [3+2=5]

Answer

Symptoms expressed in a child affected with Thalassae:

  1. Less formation of Hemoglobin
  2. Anaemia
  3. Excessive deposition of iron
  4. Unusual formation of bones
  5. Stunted growth
  6. Cardiac problems.

Suggestions to be given at the time of genetic counselling in case of Thalassaemia.

  • Carrier couples should not take any child.
  • To undergo proper blood lest prior to pregnancy.
  • They should be aware of the possible complications of the baby.

Question 4.4

Describe the brief outline of the chemical origin of life mentioning Millerand Urey’s experiment. [5]

Answer

Here is a brief outline of the chemical origin of life mentioning Miller and Urey’s experiment:

  • The chemical origin of life is the study of how life on Earth first arose from non-living matter.
  • The Miller-Urey experiment simulated the conditions of the early Earth and showed that organic molecules could form from non-living matter.
  • These organic molecules could have been the building blocks of the first living cells.
  • There is still much that we do not know about the chemical origin of life, but the Miller-Urey experiment was a major step forward in our understanding.

OR

Describe two major tenets of Lamarck’s evolutionary theory. How does the comparative anatomy of hearts act as proof in favour of evolutionary theory?  [3+2=5]

Answer

Here are two major tenets of Lamarck’s evolutionary theory:

  • Use and disuse: Lamarck believed that organisms could change over time in response to their environment. If an organism used an organ more, it would become stronger and larger. If an organism did not use an organ, it would become weaker and smaller.
  • Inheritance of acquired characteristics: Lamarck also believed that these acquired characteristics could be passed on to offspring. For example, if a giraffe’s neck became longer because it was constantly reaching for leaves, its offspring would also have longer necks.

Question 4.5

Analyse the role of bacteria at any three steps of the nitrogen cycle. “Luxurious and comfortable lifestyle is one of the major reasons for air pollution” –  Support the statement with arguments. [3 + 2 = 5]

Answer

Here are the roles of bacteria in three steps of the nitrogen cycle:

Nitrogen fixation: Bacteria are responsible for converting atmospheric nitrogen gas (N2) into forms that plants can use, such as ammonia (NH3). This process is called nitrogen fixation.

  • Free-living bacteria: Some bacteria, such as Azotobacter and Clostridium, can fix nitrogen in the soil.
  • Symbiotic bacteria: Other bacteria, such as Rhizobium, form symbiotic relationships with plants. These bacteria live in nodules on the roots of legumes, such as peas and beans.

Nitrification: Bacteria convert ammonia into nitrites (NO2–) and then into nitrates (NO3–). This process is called nitrification.

  • Nitrosomonas: Bacteria in the genus Nitrosomonas convert ammonia into nitrites.
  • Nitrobacter: Bacteria in the genus Nitrobacter convert nitrites into nitrates.

Denitrification: Bacteria convert nitrates back into nitrogen gas. This process is called denitrification.

  • Pseudomonas: Bacteria in the genus Pseudomonas can denitrify.
  • Thiobacillus denitrificans: Bacteria in the genus Thiobacillus can denitrify.

A luxurious and comfortable lifestyle is one of the major reasons for air pollution. This is because many of the activities that we associate with a luxurious and comfortable lifestyle, such as driving cars, using air conditioners, and burning fossil fuels, produce air pollutants.

OR

Give two examples of animal biodiversity endangered by the pollution of the river Ganga. Explain any three incidences which occurred as a result of the disruption of the nitrogen cycle.

Answer

Two examples of animal biodiversity endangered by the pollution of the river Ganga

  1. Gangetic dolphin
  2. Gharial

Here are three incidences which occurred as a result of the disruption of the nitrogen cycle:

  • Algal blooms: When the nitrogen cycle is disrupted, it can lead to algal blooms. These are large growths of algae that can occur in water bodies. Algal blooms can be harmful to aquatic life and can also produce toxins that can be harmful to humans.
  • Eutrophication: Eutrophication is a process by which water bodies become enriched with nutrients. This can lead to the growth of algae and other aquatic plants, which can eventually deplete the oxygen levels in the water, leading to the death of fish and other aquatic life.
  • Nitrate contamination: Nitrates are a form of nitrogen that can be found in groundwater and surface water. When nitrates are present at high levels, they can be harmful to human health. Nitrates can also contribute to the formation of smog.

Question 4.6

“Change of climate and global warming is a problem resulting from the increasing human population” － Summarize what impacts it might exert on the environment. “Children and adults both suffer from different respiratory problems during the winter”－ Write two names of such problems and state one symptom of each of them. [3+2=5]

Answer

Due to anthropogenic activity, these are pollution, deforestation and other degradation in the environment. These changes in atmospheric conditions, cause natural changes and global warming. Greenhouse gases are increased. Melting of ice and rise of sea level are occurring. Loss of biodiversity, acid rain, heavy rainfall etc. are other impacts on the environment due to changes in climate and global warming resulting from the increasing human population.

(i) Asthma:

Symptoms can include wheezing, shortness of breath, chest tightness, and coughing.

(ii) Bronchitis-

Symptoms include a productive cough (coughing up mucus), wheezing, shortness of breath, and chest pain.

OR

You have identified three environmental problems while on research in Sunderbans －

  1. Disbalance in prey-predator number.
  2. Destruction of mangrove plants due to urbanization.
  3. Submergence of islands due to rising sea level

Analyse what impacts might exert on biodiversity. Write the location of the Sundaland hotspot and one important species of its biodiversity. [3+2=5]

Answer

Disbalance in prey-predator number – The shrinking of mangrove vegetation has resulted in a reduction in the number of herbivores and as a result of which they carni- vores are becoming endangered in this case the number of tigers is going down and moreover they are getting killed. Gradually the ecosystem will be unbalanced.

Destruction of Mangrove plants due to urbanization- Due to urbanization the mangrove plants are destroyed. The destruction of the Mangrove forest and the progressing human settlement has resulted in the loss of habitat for the animals, making them endangered and vulnerable. As a result, they may get extinct in future.

Submergence of Islands Due to rising sea level:-

An increased number of islands are getting submerged due to increasing water levels as a result of which the habitat is getting shrunk and that has reduced the habitat. In want of habitat and food the species of various tropic levels will be lost.

Location of sundaland hotspot:- It is a biogeographical region of South Eastern Asia.

Important species:- Elephant

Group – E

[For External Candidates Only]

5. Answer any four questions: [1×4=4]

Question 5.1

Mention one feature of striated muscle.

Answer

One feature of striated muscle is that it has alternating light and dark bands. These bands are caused by the arrangement of protein filaments in the muscle cell.

Question 5.2

Which cell organelle is referred to as the “factory for protein synthesis”?

Answer

The cell organelle that is referred to as the “factory for protein synthesis” is the ribosome.

Question 5.3

Give an example of an organism having prokaryotic cells.

Answer

An example of an organism having prokaryotic cells is E. coli.

Question 5.4

Give an example of a hydrophilous flower.

Answer

An example of a hydrophilous flower is a water lily.

Question 5.5

Write one function of the centrosome.

Answer

One function of the centrosome is to organize the microtubules that form the spindle during cell division.

6. Answer any three questions: [2×3=6]

Question 6.1

Write two features of connective tissue.

Answer

Two features of connective tissue are:

  • It is made up of cells, fibres, and ground substances.
  • It is found throughout the body, providing support, protection, and insulation.

Question 6.2

Write two functions of Parenchyma tissue.

Answer

Two functions of parenchyma tissue are:

  • Storage of food and nutrients.
  • Production of new cells.

Question 6.3

Mention two locations of meristematic tissue in the plant body.

Answer

Two locations of meristematic tissue in the plant body are:

  • Apical meristem: This is found at the tips of roots and shoots, and it is responsible for the growth of the plant in length.
  • Lateral meristem: This is found in the vascular tissues of the plant, and it is responsible for the growth of the plant in thickness.

Question 6.4

Write the names of any two important physiological processes occurring in organisms.

Answer

Two important physiological processes occurring in organisms are:

  • Respiration: This is the process by which organisms break down food molecules to release energy.
  • Photosynthesis: This is the process by which plants use sunlight to convert carbon dioxide and water into glucose and oxygen.
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