Question

1) write four uses of nylon? 2) give reasons for thefollowing? a) immersion rods for heating liquids and made up of metals -- b) copper cannot display zinc from its salt solution-- 3) avoid plastic as far as possible' . do you agree with this statement ?give your reasons. what are the materials that can be used in place of plastics ? 4) a child living in coastal region tests the drinking water and also sea water with his tester to deflect a compass needle . in which case the deflection will be more and why ? 5) write a functionofthe following? a) pseudopodia b) cell membrane c) nucleus 6) draw the nitrogen cycle and label it. 7) draw a animal cell and labelit.how does it differ froma plant cell ( any two points)

Answer 1

Uses of nylon: It is used for makig toothbrushes, socks, curtains, sleeping bags, car seat belts etc. It is used for making parachutes and ropes for rock climbing. 2. a) Immersion rods are made of metallic substance as they are good conductors of heat and electricity. b) as zinc is more reactive than copper. 3. Because it is environmental hazard and also non biodegradable. 7. Animal cell 1. Cell wall is absent. 2.Plastids are absent. 3. No or small vacuoles are present. Plant cell 1. Cell wall is present. 2. Plastids are present. 3. Large vacuoles are present. 5 c) nucleus is a very important part of cell. It is located on the centre of the nucleus. It can be stained easily with a microscope. It is separated by cytoplasm by a membrane called nuclear membrane. It is also called control centre of a cell. It contains chromosomes that carries genes which helps in the transfer of characteristics from parents to offsprings.