This is correct because melting of ice is a physical change and is reversible.

Both these changes can be controlled. Rusting of iron happens over a long period of time and if treated right it can be prevented. Similarly milk can be prevented from spoiling by turning into curd or by boiling and pasteurization.

This is the correct option. All the statements are correct. 

This is an irreversible change. The paper cannot be retrieved back after it has burned.

This is the correct answer. Both these changes are desirable.

This statement is correct. This would become irreversible if it were cooked but now it iws reversible as it is just a physical change.  

This is the correct answer. Fast changes occur over a short interval of time. 

This is the correct answer. Germination of a seed will create a plant and this is an irreversible change.

This is the correct answer. Formation of coal is a slow change. It takes a very long time for coal to form.

This is the correct option. All these are exothermic changes. Changes that absorb energy are called endothermic changes. Preparation of food by green plants is an endothermic change.

Photosynthesis is considered as an endothermic reaction because in this process energy in the form of sunlight is absorbed. This statement is false.

This is the correct choice. Both these are correct.

This is a periodic change. It will happen after a time.

This is the correct answer. Air can be compressed. Metal can be hammered into sheets. Sand is insoluble in water.

 This is the correct matching. Burning of wood is a chemical change. Arrival of spring is a periodic change. Formation of clouds is a physical change.