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?

Describe the process of urine formation in kidneys.

How do carbohydrates, fats and proteins get digested in human beings?

Name the raw materials required for photosynthesis. How do plants obtain these raw materials?

There are five animals P, Q, R, S and T. The animal P always lives in water and has gills for breathing. The animal Q can stay in water as well as on land and can breathe both, through moist skin and lungs. The animal R lives in soil and breathes only through its skin. The animal S lives on land and breathes through spiracles and tracheae. And animal T lives in water and breathes through its cell membrane.

1. Which of the animals could be Amoeba?
2. Which of the animals could be frog?
3. Which animal could be fish?
4. Which animal could be grasshopper?
5. Which animal could be earthworm?

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 in animals.

A liquid X of colour Y circulates in the human body only in one direction: from body tissues to the heart. Among other things, liquid X contains germs from cells and dead cells. The liquid X is cleaned of germs and dead cells by a special type of white blood cells called Z. This cleaned liquid is then put into blood circulatory system in subclavian veins.

1. What is (i) liquid X and (ii) colour Y?
2. What are Z.
3. The liquid X is somewhat similar to a component of blood. Name this component.
4. Why is liquid X not red?

Water and dissolved minerals get into the root hair of a plant by a process called A and enter the conducting tissue B. The process C helps the water and dissolved minerals to move up through the tissue B in roots and stem, and reach the leaves of a plant. In the leaves food is made by a process D. This food is then transported to all the parts of a plant through tissue E. The process of distributing food made in the leaves to all the parts of the plants is called F.

1. What are (i) A, (ii) B, (iii) C, (iv) D, (v) E, and (vi) F?
2. Which tissue is made up of living cells: B or E?
3. Which tissue, B or E, contains sieve tubes?
4. Which tissue, B or E, contains tracheids?

During the respiration of an organism A, 1 molecule of glucose produces 2 ATP molecules whereas in the respiration of another organism B, 1 molecule of glucose produces 38 ATP molecules.

1. Which organism is undergoing aerobic respiration?
2. Which organism is undergoing anaerobic respiration?
3. Which type of organism, A or B, can convert glucose into alcohol?
4. Name one organism which behaves like A.
5. Name two organisms which behave like B.