Two very small organisms X and Y both reproduced by the method of budding .Organism X is industirally very important because it is used in making alcohol from sugar. It is also used in making bread. Organism Y is a tiny animal having tentacles which lives in water.
d) What is organism Y ?

A, B and C are three living organisms. The organism A is a unicellullar fungus which can live without air. It is used in the commercial production of an organic compound P from molasses. The organism B is a unicellular animal which lives in water and feeds and moves by using pseudopodia. It breathes through an organelle Q. The organism C is an tiny animal which acts as a carrier of malarial parasite. It breathes and respires through a kind of tiny holes R and air-tubes S in its body. (a) What are organisms (i) A (ii) B, and (iii) C ? (b) Name (i) P (ii) Q (iii) R, and (iv) S (c) Which organism/organisms undergo aerobic respiration ? (d) Which organism/organisms undergo anaerobic respiration ?

An organism X having breathing organs A lives on land. When organism X goes under water, it cannot survive for a long time unless carrying an oxygen cylinder. On the other hand, the organism Y having breathing organs B always lives in water and if taken out of water, it dies after a short while. A third organism Z having breathing orgains C and D which lives on the banks of ponds, lakes and rivers can survive on land as well as in water equally well. (a) What could organism X be? Name the breathing organs A. (b) What could organism Y be? Name the breathing orgains B. (c) What could organism Z be ? Name the breathing organs C and D (d) Out of X, Y and Z, which organism is (i) amphibian, (ii) aquatic, and (iii) terrestrial ?

There were lot of organisms A in the crop fields in an area. These organisms used to feed on organisms B also present in the crop fields but which damaged the standing crops. One day some people arrived in the fields and killed all the organisms A so that they could remove their C for making fancy items which were in great demand. Due to large scale killing of A, the population of B increased too much damaging all the crops in the area and causing a famine-like situation. Apart from A, there is another organism D which can also kill and eat B. Name A, B C and D.

The organ A which is located inside the skull of our body is protected by a bony box B and it is surrounded by three membranes C. the space between the membranes is filled with a liquid D which protects the organ A from mechanical shocks. The organ A in combination with another organ E makes up the central nervous system. (a) What is organ A? (b) What are (i) B (ii) C, and (iii) D ? (C) Name the organ E. (d) While walking barefooted, it we happen to step on a sharp piece of stone, we immediately lift our foot up. which of the two organs, A or E, is directly involves in this action? (e) If we step out from a darkened room into bright sunshine, we close our eyes for a moment. Which of the two organs, A or E, is directly involves in this action?