Useful and Harmful Microbes — Science STD 9 — Question

Fill in the following blanks with suitable word:
To every action, there is an _______ and _______ reaction.

Fill in the blanks in the following statements:
The electron has ________ charge, the proton has _________ charge, and the neutron has _________ charge.

Fill in the following blanks with suitable word:
The weight of an object on the earth is about _______ of its weight on the moon.

Complete the following statements:
Isotopes have different mass numbers because their nuclei contain different number of _________.

Fill in the following blanks in respect of an atom of an element:

Number of protons	Number of neutrons	Mass number	Atomic number	Number of electrons	Valency
11	12	..............	..............	..............	..............

Fill in the following blanks with suitable words:
It is possible for something to accelerate but not change its speed if it moves in a ______.

Fill in the following blanks with suitable word:

Force acting on a unit area is called _______.

Fill in the following blanks with suitable word:
In order that the force of gravitation between two bodies may become noticeable and cause motion, one of the bodies must have an extremely large ______.

Glandular epithelium : Secretion of sweat, oil :: Cuboidal epithelium: