Heat — Science STD 7 — Question

On a very cold morning, Boojho and Paheli were talking with each other as they walked down to their school. They observed that the air coming out of their mouth looked like smoke. They were amazed and wondered how it happened. Help them to find the answer.

Does transpiration serve any useful function in the plants? Explain.

Do you know the action of saliva on food?

Sunlight, chlorophyll, carbon dioxide, water, and minerals are raw materials essential for photosynthesis. Do you know where they are available? Fill in the blanks with the appropriate raw materials.
(a) Available in the plant : ______
(b) Available in the soil : ______
(c) Available in the air : ______
(d) Available during day : ______

Differentiate between distance and displacement.

State some adaptation of animals living in tropical rain forest.

Plants are known as the producers of a food chain. Give reason.

Write three precautions that need to be taken in cyclone prone areas.

An erect and enlarged image of an object is formed on a screen. Explain how this could be possible.

Boojho's uncle was hospitalised and put on dialysis after a severe infection in both of his kidneys.
(i) What is dialysis?
(ii) When does it become necessary to take such a treatment?