The partially digested food coming from the stomach of a person enters a long and narrow organ A in his body. The organ A receives the secretion of two glands: liver and pancreas. Liver secretes a greenish - yellow liquid B which is normally stored in the organ C. Pancreas secretes pancreatic juice which contains three digestive enzymes D, E and F. The intestinal juice completes the process of digestion of food. The inner wall of organ A has millions of tiny finger - like projections G which help in the rapid absorption of digested food into blood stream. The undigested part of food then passes into wider tube H which absorbs most of the water from undigested food. The last part of tube H called I stores this undigested food (or waste) for some time. The undigested food is then passed out though opening J as faeces in the process known as K.

1. Name the organ A.
2. Name liquid B and organ C.
3. What are the digestive enzymes D, E and F?
4. Name the projections G present on the inner wall of organ A.
5. Name Tube H, Part I, Opening J and Process K.

Where does anaerobic respiration occur in human body?

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?

Why do we need a proper transportation system in plants?

State the location of salivary glands.

Distinguish between photosynthesis and respiration.

What is the difference between external and internal respiration.

1. A gas is released during photosynthesis. Name the gas and also state the way by which the gas is evolved.
2. What are stomata? What governs the opening and closing of stomata?

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?

Consider the following chemical reactions which take place in different organisms/ tissues under various conditions:

1. Glucose → Respiration → Respiration Ethanol + Carbon-dioxide + Energy.
2. Glucose → Respiration → Respiration Carbon-dioxide + Water + Energy.
3. Glucose → Respiration → Respiration Lactic acid + Energy.

1. Name one organism which respires according to equation (i) above.
2. Name one organism which respires according to equation (ii) above.
3. When and where does respiration represented by equation (iii) above take place?
4. Which equation/ equations represent aerobic respiration?
5. Which equation/ equations represent anaerobic respiration?
6. Which of the above reactions produces the maximum amount of energy?