What do you mean by desirable changes?
(i) Rain bringing water to crops.
(ii) Change of milk to curd.
(iii) Ripening of fruits.
What do you mean by change of state? How can the physical state of matter be changed?
What do you mean by the changes of state? Write the flow chart showing the complete cycle of change of state.
What do you understand by desirable and undesirable changes ? is flood a desirable or an undesirable change ? Give reasons.