Reproduction in Animals — Science STD 8 — Question

Name the substance which is needed continuously by thyroid gland to make thyroxine hormone.

State the size of image formed by a plane mirror.

What are the effects of the overuse of synthetic fertilizers on soil?

Two tiny holes are made in a plastic bucket, one near the middle part and the other just above bottom when this bucket is filled with water, the water rushes out from the bottom hole much faster than from the upper hole. What conclusion do you get from this observation?

A group of cells performing similar functions are known by a speciic term. What is it?

Name two musical instruments which produce sound by simple beaten.

A gas filled balloon moves up. Is the upward force acting on it larger or smaller than the force of gravity ?

Is there any relation between pressure and force ?

Name three characteristics which are used to describe oscillations (or vibrations).

What is muscular force? Why is it called a contact force?