Cell Structure and Functions — Science STD 8 — Question

Why should paper be saved? Prepare a list of ways by which you can save paper.

Tashu saw her mother keeping the wheat grains on the terrace in a sunny day before storing them. She was confused to see this as she thought the grains will get dirty if kept in open and approached her mother for clearing her doubts.
Her mother explained Tashu the reason behind her act. Tashu then helped her mother to carry the grains to the terrace happily.
(i) The grains were kept on the terrace. Can you suggest a reason ?
(ii) Is it necessary to keep the grains in the Sun? Why or why not ?

Make a sketch of the human muscle cell. What are the functions do muscles cell perform?

State three difference between a plant cell and animal cell?

Is it possible for a substance to be classified as both an element and a compound? Explain why or why not.

Explain the difference between pure air and polluted air.

You see your image in a plane mirror? State two characteristics of the image so formed.

Manu was heating oil to fry potato chips. The cooking oil all of a sudden caught fire, he poured water to extinguish the fire. Do you think, this action was suitable ? If yes, why? If not, why not? In such a condition what should Manu have done ?

Give reasons for the following: Mosquitoes can be controlled by preventing stagnation of water though they do not live in water. Why?

What is a plastid? What is the name of green plastids present in plant cells?