Give scientific reasons for the burning of fuels may be an undesirable change.
Give scientific reasons for the burning of paper is an irreversible change.
Give scientific reasons for the burning of cooking gas is a fast change.
4. Give two examples where burning of a substance is an undesirable change.
What do you understand by desirable and undesirable changes ? is flood a desirable or an undesirable change ? Give reasons.
A change may be desirable and undesirable at the same time for different sets of people