(a) What do you understand by "watershad management" ? List any two advantages of watershed management.
(b) "Human beings occupy the top level in any food chain". What are the consequences of on our body ?

What do you understand by infertility ? Mention any three causes of infertility.

What do you mean by change of state? Name any two change of state.

What do you understand by the term respiratory diseases ? Name any three common respiratory diseases.

(a) What do you understand by the change of phase of a substance ? (b) Is there any change in temperature during the change of phase ? (c) Does the substance absorb or liberate any heat energy during the change of phase ? (d) What is the name given to the energy absorbed during a phase change ?

(a) What do you understand by the term potential energy ? (b) State two factors which determine potential energy of a body. (c) Give four examples of potential energy.

What do you understand by the term couple? State its effect .Give two examples in our daily life where couple is applied to turn a body.

(a) What do you understand by the term kinetic energy ? (b) State two factors which determine kinetic energy of a body. (c) Give four examples of kinetic energy. (d) Two bodies have equal mass. However, the speed of the one body is twice the speed of other body. what is the ratio of kinetic energy of the two bodies ?

(a) What was the basis of Mendeleev's Classification of elements ? (b) List two achievements of Mendeleev's periodic tables. (c) List any two observations which posed a challenge to Mendeleev's periodic law.