(a) What is meant by 'environment' ?
(b) What type of substances are the major pollutants of the environment ? Name two such substances.
(c) Name the organisms whose uncontrolled activities are damaging the environment.
(d) Explain why, it is better to use paper begs than plastic bags.

(a) What is meant by 'reflection of sound'? What type of surfaces are the best for reflecting sound? (b) Name any two objects which are good reflectors of sound. (c) State the laws of reflection of sound.

(a) What does this diagram depict? (b) What is meant by the largest and the smallest in the picture. (c) Name the compound used to visualise them. (d) Define elution

a)What is Biomass. b) An environmentalist on visit to your school suggested the use of three R's to save the environment. Explain what he meant by three 'R's and how you would follow his advice at home.

(a) What are vitamins? Name any two vitamins. (b) Why vitamin A and C are essential to us? Name one important source of each.

Name : (a) two substances which can sublime (b) two substances soluble in water (c) two substances insoluble in water (d) four substances that can be used as filters.

(a) Name the organism which lives in pollution free environment. (B) Name any two acellular infective agents which are not included in five kingdoms of Whittaker. (c) Name a sexually transmitted disease caused by animal virus in Human being.

there are three substance X,Y and Z , the substance X, does not have a fixed melting point or boiling and it still shows the individual properties of its constituents ,the substance Y has a fixed melting point and boiling but it cannot be broken down into simpler substance by any chemical means the substance Z is also a pure substance divided by electroysis into two substance which belong to the same class of substance as Y (a) what type of substance could X be ? Name one substance like X. (b) what type of substance could Y be ? Name one substance like Y. ( c) what type of substance could Z be ? Name one substance like Z. ( d) which process involves absorption or release of an appreciable amount of energy : formation of substance X or formation of substance Z.? ( e) Name the three group into which all the substance like Y are divided on the basis of their properties .