Page 5 - ACTIVE SCIENCE 4 TOC

8. Spread the leaf evenly on a white tile.

9. Add a few drops of iodine solution to the leaf and note the
observations.

Observation : The leaf would change its colour to blue-black.

Conclusion : This change of colour to blue-black indicates the presence of starch.

Why do Leaves Change Colour in Winter?

During winter, leaves are unable to prepare food. There is no sufficient light or

water for photosynthesis. They live off the food they synthesised and stored during
summer. The chlorophyll disappears. The bright green colour slowly changes to
yellow and then orange. Starch that was stored in the leaves as a by product of

photosynthesis turns red due to cool temperature.

Let’s Recapitulate

Fill in the blanks with only one word.

1. The leaves turn _____________ during winters.
2. During winter, there is no sufficient light and water for_____________.

3. The opening and closing of stomata is controlled by_____________.

4. _____________ has a waxy coating that protects the leaf.
5. _____________ are the tiny structures located in the cells of leaves and green stems.

I nterdependence of Plants and Animals

Survival of plants and animals depends entirely
on how much they depend on each other. Through Factual Study
the process of photosynthesis, plants prepare their Plants provide us food,

own food. This food is a source of nourishment for shelter, fuel, building

all other life forms. The leaves exhale oxygen which material, medicines, etc.
is majorly required by humans and animals for Some plants have
breathing. Therefore, animals and humans largely medicinal value as well.

depend on plants.

Animals may be – herbivorous, carnivorous and omnivorous. Herbivores eat plants,

carnivores eat other small plant eating animals, and omnivores eat both plants and

12 Active Science-4