Explain the three pathways of breakdown in living organisms.

‘Aerobic respiration produces more ATP than anaerobic respiration’. Justify this statement.

1. Define excretion.
2. Name the basic filtration unit present in the kidney.
3. Draw excretory system in human beings and label the following organs of excretory system which perform following functions:

1. Form urine.
2. Is a long tube which collects urine from kidney.
3. Store urine until it is passed out.

1. Draw a sectional view of the human heart and label on it, Aorta, Right Ventricle and Pulmonary Veins.
2. State the functions of the following components of transport system:

1. Blood.
2. Lymph.

Differentiate between left lung and right lung of humans.

Given below is the experimental set-up to establish that one of the atmospheric gases is essential for photosynthesis in plants.

1. Name the atmospheric gas which is essential for photosynthesis.
2. What is kept in watch-glass in figure 'a' and why?
3. Write the balanced chemical equation for the process of photosynthesis.
4. When do the desert plants takeup carbon dioxide and perform photosynthesis?

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.

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

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

When a person eats sugary food, then organisms A present in his mouth act on sugar to produce a substance B. The substance B first dissolves the calcium salts from the top part C of the tooth and then from its middle part D forming holes E. These holes ultimately reach the part F in the lower part of tooth which contains nerves and blood vessels. The substance B irritates the nerve endings inside the tooth causing toothache.

1. What are (i) organisms A, and (ii) substance B?
2. What are (i) part C, and (ii) part D, of tooth known as?
3. By what name are the holes E in the tooth known?
4. Name the part F of the tooth.
5. What will happen if organisms A reach part F of the tooth known?