The World of Metals and Non-metals — Science STD 7 — Question

State whether the following statements are True or False. If false, correct them.
In the process of obtaining wool from fleece, sorting is done after scouring.

Why is plastic used on electrical wires?

What does the windpipe divide into?

If Boojho covers a certain distance in one hour and Paheli covers the same distance in two hours, who travels in a higher speed?

What per cent of total water on the earth is actually available for our use?

Plants help the development of the soil. How?

What is the function of the circulatory system in humans?

Name the devices used by our ancestors to measure the time before pendulum clocks.

Consider if one half of a convex lens is covered with a black paper, then state whether this lens produces a complete image of the object.

Name the term used for organisms that respire using anaerobic mode. Give an example of any such organism.