Why don't gases have definite shapes and volumes?

Why do solids have a definite volume ?

Solids have definite shapes and volumes, why ?

Collect the following articles-a pen, a book, a needle and a piece of thread. Sketch the shape of the above articles in your notebook by moving a pencil around them. Do all these have a definite shape, distinct boundaries and a fixed volume ?

Why do gases have neither a definite shape nor a definite volume ?

Why do metals aquire different shapes?

Why do histones have the charge and give their use.

Why crystalline solids have a sharp melting point?

Why are solids rigid?

Name the cell that does not have a definite nucleus.