Madhyamik Class 10 Life Science Solved Paper 2017
Life Science
Time – Three Hours and Fifteen Minutes
(First fifteen minutes for reading the question paper only)
Full Marks – 90
(For Regular and Sightless Regular Candidates)
Full Marks – 100
(For External and sightless External Candidates)
For Regular candidates, the questions for Group ‘A’, ’B’, ‘C’, and ‘D’ will have to be answered.
Special Instruction for Sightless Candidates
In Group ‘D’ instead of Question No. 4.1, 4.1 (A) will also have to be answered in addition to Group ‘A’, ‘B’, ‘C’ and D.
Instructions regarding the number of questions to be attempted have been indicated at the beginning of each group.
Figures in the margin indicate full marks for each question Special credits will be given for answers which are brief and to the point.
Marks will be deducted for spelling mistakes, untidiness and bad handwriting.
Group – A
1. Multiple choice question.
Question 1.1
Some flowers are open after sunrise and close after sunset. This is –
- Photonasty
- Seismonasty
- Chemonasty
- Thermonasty
Answer
Photonasty.
Explanation
Photonasty is a nastic movement that is associated with changes in light intensity.
Question 1.2
A person affected with Diabetes Mellitus is unable to secrete which of the following hormone in adequate quantity-
- Adrenaline
- Insulin
- Thyroxine
- Testosterone
Answer
insulin
Explanation
A person affected with Diabetes Mellitus cannot secrete insulin in adequate quantity. Insulin is a hormone produced by the pancreas that helps the body use glucose for energy.
Question 1.3
The part of the human brain associated with controlling body temperature is
- Thalamus
- Cerebellum
- Hypothalamus
- Medulla
Answer
hypothalamus
Explanation
The part of the human brain associated with controlling body temperature is the hypothalamus.
Question 1.4
You have observed the separation of two sister chromatids at one stage of mitotic cell division the stage is
- Prophase
- Telophase
- Anaphase
- Metaphase
Answer
anaphase
Explanation:
The stage of mitosis where the separation of two sister chromatids occurs is anaphase.
Question 1.5
Which of the following pair is correct
- Budding-Yeast
- Fragmentation
- Sphere-formation-amoeba
- Regeneration-Dryopteris
Answer
Budding-Yeast
Explanation:
The correct pair is Budding-Yeast. Budding is a type of asexual reproduction in which a small bud grows off of the parent cell.
Question 1.6
Which phase of human development is associated with the maturity of reproductive organs and reproductive gland –
- Childhood
- Adolescence
- Late Adulthood
- Infancy
Answer
adolescence
Explanation:
The phase of human development associated with the maturity of reproductive organs and reproductive glands is adolescence.
Question 1.7
Which of the following traits in pea plant is recessive –
- Wrinkled seed
- Yellow-coloured seed
- Purple-coloured flower
- Axial flower
Answer
wrinkled seed
Explanation:
The recessive trait in pea plant is a wrinkled seed. The dominant trait is a round seed. The other options are all dominant traits.
Question 1.8
How many types of gametes are formed by pea plants having genotype YyRr?
- 1
- 4
- 2
- 3
Answer
2
Explanation:
A pea plant with genotype YyRr is heterozygous for both the seed colour and seed shape genes. This means that it can produce two types of gametes, YR and yr. Therefore, there are 2 types of gametes formed by pea plants having genotype YyRr.
Question 1.9
The probability of haemophilic girl children born to a hodophilia carrier mother and normal father is –
- 75%
- 50%
- 100%
- 0%
Answer
50%
Explanation:
The probability of a haemophiliac girl child born to a haemophilia carrier mother and a normal father is 50%.
Question 1.10
The gas which was absent in the environment during the origin of life is –
- Hydrogen
- Oxygen
- Methane
- Ammonia
Answer
oxygen
Explanation:
The gas which was absent in the environment during the origin of life is oxygen.
Question 1.11
The feature of analogues organ is –
- Differences in origin and function are also different
- Different in origin but function are same
- Indicates divergent evolution
- Identical in origin and structure
Answer
Different in origin but function are same
Explanation:
Analogous organs are organs that have different origins but perform the same function.
Question 1.12
Which of the following absorbs the gas of the swim bladder in bony fishes –
- Red gland
- Anterior chamber
- Gastric gland
- Retia mirabilia
Answer
red gland
Explanation:
The gas in the swim bladder of bony fishes is absorbed by a structure called the red gland.
Question 1.13
Which of the following phase of the nitrogen cycle Pseudomonas is associated with-
- Nitrogen fixation
- Nitrification
- Denitrification
- Ammonification
Answer
denitrification
Explanation:
Pseudomonas is associated with the phase of the nitrogen cycle known as denitrification.
Question 1.14
One endangered species of the Eastern Himalayas biodiversity hotspot is –
- Lion-tailed macaque
- Orangutan
- Red panda
- Nilgiri thar
Answer
red panda
Explanation:
The red panda is a small, furry mammal that is native to the Eastern Himalayas and the Eastern Himalayas biodiversity hotspot. It is listed as Endangered on the IUCN Red List due to habitat loss, poaching, and competition from other animals.
Question 1.15
The diseases associated with air pollution are –
- Diarrhoea, Typhoid, Hepahepatitis,
- Hepahepatitis, Bronchitis, Deafness
- Bronchitis, Asthma, Lung cancer
- Lung cancer, Polio, Malaria
Answer
Bronchitis, Asthma, Lung cancer
Explanation:
Air pollution, particularly the presence of pollutants such as fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone (O3), can have harmful effects on the respiratory system.
Group B
2. Answer the following question (alternatives are to be noted).
Fill in the blanks:
Question 2.1 – 2.6
- The process of necessary adjustment of the lens’s focal length in human eyes is called ____.
- Adenine is a __ type of nitrogenous base.
- __ is a disease created by sex-linked genes.
- The earliest ancestor in the evolution of horses is ___.
- An inflammable greenhouse gas produced from the paddy field is __.
- ____ is a biosphere reserve located in West Bengal.
Answer
- The process of necessary adjustment of the focal length of the lens in human eyes is called accommodation.
- Adenine is a purinic type of nitrogenous base.
- Hemophilia is a disease created by sex-linked genes.
- The earliest ancestor in the evolution of horses is Hyracotherium.
- An inflammable greenhouse gas produced from the paddy field is methane.
- Sundarbans is a biosphere reserve located in West Bengal.
Decide whether the following statements are true or false (any five)
Question 2.7
Gibberellin hormone prevents immature shedding of the leaf of plants.
Answer
True
Reasons: Gibberellins are plant hormones that promote cell division and elongation. They can also prevent the abscission of leaves, which is the natural process of leaf shedding.
Question 2.8
Ovum is only produced as a result of mitosis.
Answer
False.
Reasons: The ovum, or egg cell, is produced by meiosis, not mitosis. Meiosis is a type of cell division that reduces the number of chromosomes in half.
Question 2.9
Self–pollination can be exercised in pea plant flowers according to the need.
Answer
True.
Reasons: Pea plant flowers have both male and female reproductive organs. This means that they can self-pollinate, which is the process of pollen from the same flower fertilizing the egg cell.
Question 2.10
The fundamental tenet of the evolutionary theory of Darwin is the process of natural selection.
Answer
True.
Reasons: Charles Darwin’s theory of evolution by natural selection is based on the idea that individuals with traits that make them better suited to their environment are more likely to survive and reproduce.
Question 2.11
A degradable pollutant is responsible for biomagnification.
Answer
False.
Reasons: Biomagnification is the process by which pollutants become more concentrated as they move up the food chain.
Question 2.12
Flagella is the locomotory organ of Paramecium.
Answer
False.
Reasons: Flagella is not the locomotory organ of Paramecium. Paramecium is a single-celled organism belonging to a group of ciliates. It moves using numerous hair-like structures called cilia.
Match the right column with the left column: (Any five)
| Column–A | Column–B |
|---|---|
| 2.13) Blind Spot | a) Pollution of groundwater |
| 2.14) Cytokinesis | b) The point of connection of the retina and optic nerve |
| 2.15) 44A+XY | c) Homologous organs |
| 2.16) Wings of bats and birds | d) Formation of cell plates |
| 2.17) Arsenic | e) Pollen grain |
| 2.18) Transfer to stigma | f) Sound pollution |
| g) Chromosomal attachments of human male |
Answer
2.13. – (b), 2.14. – (d), 2.15. – (g), 2.16. – (c), 2.17. – (a), 2.18. – (e)
Answer in a single word or in a single sentence (any six) :
Question 2.19
Choose the odd one and write it: TSH, ACTH, GTH, CSF
Answer
CSF
Explanation: TSH (Thyroid-stimulating hormone), ACTH (Adrenocorticotropic hormone), and GTH (Gonadotropin hormone) are all hormones produced by the pituitary gland.
Question 2.20
Write one function of the myelin sheath.
Answer
Myelin sheath increases the rate of transmission of nerve impulses.
Question 2.21
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.
Prophase: Disappearance of nuclear membrane and nucleolus:: ___: Reappearance of nuclear membrane and nucleolus.
Answer
Telophase
Question 2.22
Give an example of a variation inherited in man along with the generation.
Answer
Attached ear/ Common tongue
Question 2.23
Which type of chromosome in humans carries the gene responsible for the disease thalassemia?
Answer
Attached ear/ Common tongue
Question 2.24
Mention one morphological adaption of the cactus to prevent transpiration.
Answer
Modified into spines is one morphological adaptation of cactus to prevent transpiration.
Question 2.25
Among the following four terms one includes the other three, Find out that term and write it:
Embryo, meristematic tissue, Seed, Cryopreservation.
Answer
Cryopreservation
Question 2.26
Write the name of the cause of the latest concern regarding the environment of Sundarbans.
Answer
Global warming or pollution is the cause of the latest concern regarding the environment of Sundarbans.
Group C
3. Answer any 12 questions in 2-3 sentences out of 17 questions given below:
Question 3.1
Write two differences between tropic movement and nastic movement.
Answer
| Tropic Movements | Nastic Movements |
|---|---|
| Directional | Non-directional |
| Growth-dependent | Growth-independent |
Question 3.2
Write two roles of GTH in the secretion of hormones from the reproductive glands in the human body.
Answer
GTH (Gonadotropin) plays two important roles in the secretion of hormones from the reproductive glands in the human body:
- Stimulation: GTH stimulates the production and secretion of hormones from the reproductive glands, such as the ovaries in females and the testes in males.
- Feedback Regulation: GTH also provides feedback regulation to maintain hormonal balance.
Question 3.3
Categorize the following actions as natural or inherited reflex actions.
The willingness of infants to breast-feeding, Cycling, Sneezing, and Catching ball by wicket-keeper with swiftness
Answer
| Action | Natural Reflex Action | Inherited Reflex Action |
|---|---|---|
| The willingness of infants to breast-feeding | Natural | Inherited |
| Cycling | Natural | – |
| Sneezing | Natural | – |
| Catching the ball by the wicket keeper with swiftness | – | Inherited |
Question 3.4
Write the parts of the central nervous system and peripheral nervous system.
Answer
Central Nervous System (CNS):
- Brain: The control centre of the nervous system, responsible for processing information, coordinating body functions, and controlling behaviour.
- Spinal Cord: The long, cylindrical structure that connects the brain to the rest of the body and serves as a pathway for transmitting signals between the brain and peripheral nerves.
Peripheral Nervous System (PNS):
- Nerves: Bundles of nerve fibres that extend from the CNS to various parts of the body, transmitting sensory information from the body to the CNS and motor commands from the CNS to the muscles and glands.
- Ganglia: Clusters of nerve cell bodies located outside the brain and spinal cord, involved in the processing of sensory information and coordination of motor functions at a local level.
Question 3.5
Write two importance of the cell cycle.
Answer
The two importance of the cell cycle in very short:
- Growth and development: The cell cycle allows for the growth and development of organisms by allowing cells to divide and create new cells.
- Repair and maintenance: The cell cycle also allows for the repair and maintenance of organisms by allowing cells to divide and replace damaged or dead cells.
Question 3.6
Distinguish between DNA and RNA based on the following features: Pyrimidine base 5-C sugar
Answer
| Feature | DNA | RNA |
|---|---|---|
| Pyrimidine base | Thymine (T) | Uracil (U) |
| 5-C sugar | Deoxyribose | Ribose |
Question 3.7
Which agents perform the function of pollination in the following plants? Paddy Hydrilla Shimul Mango.
Answer
| Plant | Pollination Agent |
|---|---|
| Paddy | Wind |
| Hydrilla | Water |
| Shimul | Insects |
| Mango | Birds |
Question 3.8
State with an example of how the dominant trait is expressed in the experiment of hybridization.
Answer
In the experiment of hybridization dominant trait is expressed in F₁ generation and the recessive trait is suppressed. Example – In the cross between pure Black Male (B.B.) and pure white female (bb), all the guineapig in F₁ generation are phenotypically black because blackness is the dominant character. In F₁ generation black and white both types of guineapigs are produced.
Question 3.9
What would be the ratio of phenotype and genotype of F2 generation in a monohybrid experiment in case of incomplete dominance?
Answer
In incomplete dominance, the phenotypic ratio of the F2 generation is 1:2:1, the same as the genotypic ratio.
Question 3.10
Show with the help of a cross, how colour blindness is inherited.
Answer
P – Normal male × Normal Female (but carrier)
Son-1 Normal – 1 Colour blind, ∴ 1 : 1, So 50% : 50%
Question 3.11
Write the name of reactants used and one origin compound formed in the experiment of Miller and Urey in connection with the chemical origin of life
Answer
Ammonia, Hydrogen and Methane were used in the experiment on the biochemical origin of life by Miller and Urey.
Question 3.12
Write four important features modified in the evolution of the horse.
Answer
The four important features modified in the evolution of the horse:
- Size: Horses have evolved to be much larger than their early ancestors. The first horses, called Eohippus, were about the size of a fox. Modern horses can be up to 18 hands high (6 feet tall).
- The number of toes: Early horses had four toes on each foot. Over time, the number of toes has decreased, and modern horses have only one toe on each foot.
- Teeth: Early horses had teeth that were adapted for browsing on leaves. Modern horses have teeth that are adapted for grazing on grass.
- Brain size: The brain size of horses has increased over time. This is thought to be due to the need for more complex cognitive abilities, such as navigation and social behaviour.
Question 3.13
How Sundari plant excretes the excess salt in its body?
Answer
Sundari plants excrete excess salt through specialized glands called salt glands. These glands are located on the underside of the leaves. The salt glands transport salt from the leaves to the stems, where it is excreted through pores. This process is known as transpiration-driven salt efflux.
Question 3.14
Write the names of two microorganisms participating in the process of biological nitrogen fixation.
Answer
Two microorganisms that participate in the process of biological nitrogen fixation:
- Rhizobium
- Azotobacter
Question 3.15
Mention two damages as a result of acid rain.
Answer
The two damages as a result of acid rain:
- Damage to forests. Acid rain can damage trees by making it difficult for them to take up nutrients from the soil.
- Damage to aquatic life. Acid rain can make lakes and streams more acidic, which can harm fish and other aquatic life.
Question 3.16
Give four examples of damages to biodiversity as a result of global warming.
Answer
Four examples of damage to biodiversity as a result of global warming:
- Species extinction: As the Earth’s climate changes, many species will be unable to adapt and will go extinct.
- Habitat loss: As the Earth’s climate changes, many habitats will be destroyed or degraded.
- Invasive species: As the Earth’s climate changes, invasive species will become more common. These species are not native to the area and can outcompete native species for food and resources. This can lead to the decline or extinction of native species.
- Disease: As the Earth’s climate changes, the range of conditions will expand.
Question 3.17
Write the major topics regarding biodiversity documented in the People’s Biodiversity Register (PBR).
Answer
The major topics documented in the People’s Biodiversity Register (PBR) regarding biodiversity include:
- Species diversity: The PBR documents information about the various species present in a specific region or community.
- Genetic diversity: The PBR highlights the genetic diversity within species, focusing on the variations and unique traits found in populations.
- Ecosystem diversity: The PBR acknowledges the diverse range of ecosystems present in a particular area.
- Traditional knowledge: The PBR incorporates traditional knowledge and practices of local communities related to biodiversity.
Group D
4. Answer 6 questions or their alternative given below.
Question 4.1
draw a neat diagram of the vertical section of the eyeball of the human eye and label the following parts:
- Cornea
- Lens
- Vitreous humour
- Retina
Answer
Or, Draw a neat diagram of the metaphase of mitosis of a plant cell or an animal cell division and label the following parts:
- Chromosome
- Spindle fibre
- Polar region
- Centromere
Answer
Question 4.2
Explain the interrelationship among chromosomes and genes and distinguish between euchromatin and heterochromatin on the following two aspects. (a) Coiling (b) Activity
Answer
Chromosomes and genes
Chromosomes are structures that contain genetic material. They are made up of DNA, which is tightly wrapped around proteins called histones. Genes are segments of DNA that code for specific proteins.
Euchromatin and heterochromatin
Euchromatin and heterochromatin are two types of chromatin, which is the material that makes up chromosomes. Euchromatin is less condensed than heterochromatin, and it is associated with active gene expression. Heterochromatin is more condensed than euchromatin, and it is associated with inactive gene expression.
Coiling
Euchromatin is more loosely coiled than heterochromatin. This makes it easier for transcription factors to access the DNA in euchromatin, and it allows for more active gene expression. Heterochromatin is more tightly coiled, which makes it more difficult for transcription factors to access the DNA. This leads to less active gene expression in heterochromatin.
Activity
Euchromatin is more active than heterochromatin. This is because euchromatin is more accessible to transcription factors, which are proteins that bind to DNA and regulate gene expression. Heterochromatin is less accessible to transcription factors, which is why it is less active.
Or, How micropropagation is done states that happens in the following three phases of sexual reproduction of flowering plants:-
- Production of gamete or reproductive cell
- Fertilization
- Formation of the embryo and new plant
Answer
Micropropagation is a technique for rapidly producing large numbers of plants from a single plant. It involves taking small pieces of plant tissue, such as leaves, stems, or roots, and growing them in a sterile environment on a nutrient-rich medium. The cells in the tissue culture multiply and differentiate into new plants.
The three phases of sexual reproduction in flowering plants are:
- Production of gametes: Gametes are reproductive cells that can fuse to form a new plant. In flowering plants, gametes are produced by the male and female reproductive organs, the stamen and pistil.
- Fertilization: Fertilization is the process by which a male gamete (sperm) fertilizes a female gamete (egg). This process occurs when the pollen grain from the stamen lands on the stigma of the pistil. The pollen grain then germinates and grows a pollen tube, which delivers the sperm to the egg.
- Formation of the embryo and new plant: After fertilization, the zygote (fertilized egg) divides repeatedly to form an embryo. The embryo develops into a seed, which contains the new plant. The seed then germinates and the new plant grows.
Question 4.3
With the help of a checkerboard show the types of offspring that might be produced in a cross between a hybrid black guineapig and a pure white guineapig. State the law of segregation as proposed by Mendel. [3+2=5]
Answer
When a hybrid black guinea pig (Bb) is crossed with a pure white guinea pig (bb), the potential offspring can have two genotypes: Bb (black) and bb (white).
Using a Punnett square, we can represent the possible combinations:
| B | b | |
| b | Bb | bb |
| b | Bb | bb |
From the Punnett square, we can see that there is a 50% chance of producing offspring with the Bb genotype (black) and a 50% chance of producing offspring with the bb genotype (white).
The law of segregation states that actors passed from one generation to another in an unaltered manner; they separate during gamete formation, reunite during fertilization and pass to the next generation.
Or, Mention the symptoms of thalassemia disease. In many families, mothers are labelled as responsible for the birth of a daughter’s child. Demonstrate with the help of a cross, that these beliefs are not justified.
Answer
Symptoms of thalassemia:
- Fatigue and weakness
- Pale or yellowish skin
- Shortness of breath
- Delayed growth and development
Regarding the belief that mothers are responsible for the birth of a daughter’s child, let’s consider a simple cross to demonstrate why this belief is not justified:
Inheritance of traits depends on the combination of genes from both parents. Each parent contributes half of their genetic material to their child. For simplicity, let’s consider a single gene responsible for determining the sex of the child, where ‘X’ represents the X chromosome (female) and ‘Y’ represents the Y chromosome (male).
Cross: Mother (XX) x Father (XY)
Possible outcomes:
- Male child (XY): The father contributes the Y chromosome, determining the male sex of the child.
- Female child (XX): The mother contributes one X chromosome, and the father contributes another X chromosome, resulting in a female child.
From this cross, we can observe that the father’s contribution of the Y chromosome determines the birth of a male child. Therefore, it is incorrect to solely blame or attribute the birth of a daughter’s child to the mother.
Question 4.4
Mentions two features of internal structures on the basis of which, the ‘flipper of whales’ and ‘wings of birds’ are considered as homologous organs. How a worker bee of a beehive communicates with other worker bees regarding the source and location of food?
Answer
The flipper of whales and the wings of birds are considered homologous organs due to their shared internal structures. Both have similar skeletal structures, including the humerus, ulna, radius, and carpals. Additionally, their muscle structures for controlling movement are also alike. These similarities suggest a common ancestry, despite their different functions in swimming and flying, respectively.
In a beehive, a worker bee communicates food source information to others through two main dances. The waggle dance conveys the direction and distance of the food source. The angle of the dance represents the direction relative to gravity, while the duration of the waggle indicates the distance. For food sources within 75 meters, the round dance is performed, signalling the availability of food without specifying the direction. Other worker bees interpret these dances and follow the communicated information to locate the food source.
Or, Show the major evolutionary events with the help of a flow chart.
Answer
Protovirus → Virus → Bacteria → Protozoa → Multicellular organism → Chlorophyllous organism → Plants
Question 4.5
What are the causes of Asthma? What are the roles of Joint Forest Management in the conservation of biodiversity?
Answer
- Asthma: Asthma is a chronic respiratory condition that causes inflammation of the airways. The causes of asthma are not fully understood, but they are thought to include genetics, environmental factors, and allergies.
- Joint Forest Management (JFM): JFM is a community-based approach to forest management that involves local people in the planning, implementation, and monitoring of forest activities. JFM has been shown to be effective in conserving biodiversity by providing local people with a stake in the forest and by promoting sustainable forest management practices.
Or, Assess the causes of depletion of the biodiversity with proper examples.
Answer
- Habitat loss and fragmentation: This is the most significant cause of biodiversity loss. When habitats are destroyed or fragmented, species are unable to find food, mates, or suitable places to live. For example, deforestation is a major cause of habitat loss for many species of plants and animals.
- Overexploitation: This is the excessive use of a species’ resources. This can lead to the depletion of the population and even extinction. For example, overfishing has led to the decline of many fish populations.
- Invasive species: These are species that are introduced to an ecosystem and then become established and spread. Invasive species can outcompete native species for resources, leading to the decline or extinction of native species. For example, the introduction of the brown tree snake to Guam has led to the extinction of many native bird species.
- Climate change: Climate change is already having a significant impact on biodiversity. As the climate changes, species are being forced to move to new areas or adapt to the changing conditions. Some species will not be able to adapt and will go extinct. For example, rising sea levels are threatening the habitats of many coastal species.
Question 4.6
Propose two conservation measures that could be taken to increase the number of Indian one-horned rhinos. Make your opinion based on your experience of how the source of freshwater becomes polluted. [2+3=5]
Answer
Part I.
- Rhino and baby rhinos should be kept isolated in sanctuaries/ favourable environments.
- Hunting and poaching should be strictly prohibited by enacting the law.
Part II.
- Agricultural runoff containing pesticides, herbicides and fertilizers containing NO₃.
- Domestic wastewater (sewage) mainly detergents containing phosphates. Sewage helps the overgrowth of algae. This makes the water unfit for bathing and drinking.
Or, Which conditions do you consider to declare one area out of two as a biodiversity hotspot? Give two examples of ex-situ conservation.
Answer
The two conditions that need to be met for an area to be considered a biodiversity hotspot:
- It must have at least 1,500 vascular plant species as endemics
- It must have lost at least 70% of its original natural vegetation
Here are two examples of ex-situ conservation:
- Botanical gardens: Botanical gardens are places where plants are grown in a controlled environment. This allows for the conservation of plants that are threatened in their natural habitats.
- Zoos: Zoos are places where animals are kept in captivity. This allows for the conservation of animals that are threatened in their natural habitats.
Group – E
[For External Candidate Only]
5. Answer any four questions : [1×4=4]
Question 5.1
Mention one feature of unstriated muscle.
Answer
One feature of unstriated muscle is that it is not attached to bones.
Question 5.2
Which cell organelle is referred to as the “kitchen of the cell”?
Answer
The mitochondria are referred to as the “kitchen of the cell”.
Question 5.3
In which type of cell, the nucleus is not well organized?
Answer
Anucleate cells do not have a nucleus. This type of cell is found in bacteria and some other single-celled organisms.
Question 5.4
Give an example of a flower pollinated by air.
Answer
Dandelions are an example of a flower pollinated by air.
Question 5.5
Write one important feature of life.
Answer
One important feature of life is the ability to reproduce.
6. Answer any three questions : [2×3=6]
Question 6.1
Write two features of epithelial tissue.
Answer
- It is made up of tightly packed cells that form a continuous sheet.
- It has no blood vessels, so it relies on diffusion to get nutrients and oxygen.
Question 6.2
Write two functions of collenchyma tissue.
Answer
Collenchyma tissue is a type of tissue that provides support and flexibility to plant organs. Two functions of collenchyma tissue are:
- It helps to keep plant organs from collapsing.
- It allows plant organs to bend without breaking.
Question 6.3
Write two differences between plant cells and animal cells.
Answer
Two differences between plant cells and animal cells are:
- Plant cells have a cell wall, while animal cells do not.
- Plant cells have chloroplasts, which allow them to make their own food through photosynthesis. Animal cells do not have chloroplasts.
Question 6.4
Give one example for each prokaryotic and eukaryotic cell.
Answer
Examples of prokaryotic and eukaryotic cells:
- Prokaryotic cells: Bacteria are prokaryotic cells.
- Eukaryotic cells: Animal and plant cells are eukaryotic cells.
