" What do mean by the term variable valency ?Give an example."

What do you mean by variable valency ? Give two example of metals which show variable valency .

What do you understand by variable valency'? Give two examples of metals and two examples of non-metals showing variable valency.

What do you mean by the term 'food additives'? Give example.

What do you mean by the term potential energy ? Give some examples of bodies possessing potential energy ?

What do you mean by representative elements? Give an example.

What do you mean by the term triploblastic animals ? Give two examples

What do you mean by incomplete dominance ? Give one example.

What do you mean by thermosetting polymers ? Give one example.

What do you mean by brittle substance? Give any two examples.