Briefly explain the following terms:

(v) Natural immunity 

Differentiate between the following on the basis of what is given in brackets:

(i) Myopia and hypermetropia (condition of eyeball)

Differentiate between the following on the basis of what is given in brackets:

Rods and cones (pigment present)

Differentiate between the following on the basis of what is given in brackets:

Tonoplast and plasma membrane (location)

Differentiate between the following on the basis of what is given in brackets:

Wall pressure and turgor pressure (explain briefly)

Differentiate between the following on the basis of what is given in brackets:

DPT and BCG (expanded form of the vaccine)

Mention any three functions of the Red Cross.

Name any two microbes which cause diseases in man. In each case, give an example of diseases caused by them.

Mention three reasons why the growth of population has not been appreciably checked in India.

50.

Explain the following terms:
(1) Mutation