Two green plants are kept separately in oxygen-free containers, one in the dark and the other in sunlight. It was observed that plants kept in the dark could not survive longer. Give a reason for this observation.

The plant kept in the dark could not survive longer because:

• It cannot perform photosynthesis, which is essential for producing food.
• Photosynthesis requires light to convert carbon dioxide and water into glucose and oxygen.
• Without light, the plant lacks the energy needed for this process, leading to its inability to produce the oxygen necessary for respiration.

As a result, the plant in the dark cannot sustain itself and eventually dies.