Mention a change which is always1. Desirable 2. Undesirable 3. Per

1.	Mention a change which is always1. Desirable 2. Undesirable 3. Periodic
Answer» 1. Desirable: Changes that are useful to man are desirable changes, e.g. change of milk into curd. 2. Undesirable: Change that brings about destruction is an undesirable change, e.g. floods and epidemics are undesirable changes. 3. Periodic: Changes that are repeated at regular intervals of time are called periodic changes, e.g. change of day and night.

Mention a change which is always1. Desirable 2. Undesirable 3. Periodic

Answer»

1. Desirable: Changes that are useful to man are desirable changes, e.g. change of milk into curd.

2. Undesirable: Change that brings about destruction is an undesirable change, e.g. floods and epidemics are undesirable changes.

3. Periodic: Changes that are repeated at regular intervals of time are called periodic changes, e.g. change of day and night.