Explain the process of digestion of food in mouth, stomach and small intestine in human body.

Give the steps involved in photosynthesis.

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?

The process of ultra-filtration is essential in urine formation, where does this step occur in nephron?

The liquid connective tissue A circulates in our body continuously without stopping. This tissue contains a pigment B which imparts it a colour C. The tissue A consists of four components D, E, F and G. The component D fights infection and protects us from diseases. The component E helps in the clotting of tissue A if a person gets a cut. The component F is a liquid which consists mainly of water with many substances dissolved in it and component G carries oxygen from the lungs to all the parts of the body.

1. What is (i) tissue A, (ii) pigment B and (iii) colour C?
2. Name (i) D, (ii) E, (iii) F and (iv) G.
3. Name one substance (other than oxygen) which is transported by tissue A in the human body.
4. Which two components of tissue A are the cells without nucleus?
5. Name any two organisms (animals) which do not have liquid like A in their body.

What is the difference between external and internal respiration.

Excretion is different in multi-cellular organisms as compared to unicellular organisms. How?

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?

Describe the process of urine formation in kidneys.

Explain with a schematic representation the exchange of gases in tissues.