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 organs C and D which lives on the banks of ponds, lakes and rivers can survive on land as well as in water equally well.

1. What could organism X be? Name the breathing organs A.
2. What could organism Y be? Name the breathing organs B.
3. What could organism Z be? Name the breathing organs C and D.
4. Out of X, Y and Z, which organism is.

1. Amphibian,
2. Aquatic,
3. Terrestrial?

Plants absorb water from the soil. How does this water reach to the top of the tree? Explain in detail.

With a schematic diagram, explain the overall process of respiration.

Where does anaerobic respiration occur in human body?

Differentiate between left lung and right lung of humans.

1. Draw a sectional view of the human heart and label on it: Aorta, Pulmonary arteries, Vena cava, Left ventricle.
2. Why is double circulation of blood necessary in human beings?

1. Draw a diagram of excretory system in human beings and label on it: Aorta, Vena cava, Urinary bladder, Urethra.
2. List two vital functions of the kidney.

The organs A of a person have been damaged completely due to which too much of a poisonous waste material B has started accumulating in his blood, making it dirty. In order to save this person's life, the blood from an artery in the person's arm is made to flow into long tubes made of substance E which are kept in coiled form in a tank containing solution F. This solution contains three materials G, H and I in similar proportions to those in normal blood. As the person's blood passes through long tubes of substance E, most of the wastes present in it go into solution. The clean blood is then put back into a vein in the arm of the person for circulation.

1. What are organs A?
2. Name the waste substance B.
3. What are (i) E and (ii) F? Name G, H and I.
4. What is the process described above known as?

1. Draw a diagram depicting Human Alimentary Canal and label on it, Gall Bladder, Liver and Pancreas.
2. State the roles of Liver and Pancreas.
3. Name the organ which performs the following functions in humans:

1. Absorption of digested food.
2. Absorption of water.