Give suitable explanations for the following:
Hands must be washed before eating food.

Give a suitable mechanism for the following : .

Give suitable explanations for the following: Eating places must be kept free of flies.

Give suitable explanations for the following: Why does gaseous exchange continue in the lungs even during expiration ?

Give suitable explanations for the following: Why do you shiver and why do your teeth chatter when it is very cold in winter ?

Give suitable explanations for the following: Why does a person feel breathlessness at higher altitudes?

Give suitable explanation for the following: Grapes shrink when immersed in a very strong sugar solution.

Give biological explanations for the following statements: A Bat is a Mammal.

Give biological explanations for the following statements: Earthworms are very useful in agriculture.

Give biological explanations for the following statements: Leguminous plants increase soil fertility.

Give biological explanations for the following: Most molluscs also have a hard shell covering their bodies.