Distinguish between aquatic and terrestrial respiration.

State the location of salivary glands.

Explain the mechanism of photosynthesis.

Differentiate between an artery and a vein.

There is a pair of bean-shaped organs P in the human body towards the back, just above the waist. A waste product Q formed by the decomposition of unused proteins in the liver is brought into organ P through blood by an artery R. The numerous tiny filters S present in organ P clean the dirty blood by removing the waste product Q. The clean blood goes into circulation through a vein T. The waste substance Q, other waste salts, and excess water form a yellowish liquid U which goes from organ P into a bag-like structure V through two tubes W. This liquid is then thrown out of the body through a tube X.

1. What is (i) organ P and (ii) waste substance Q?
2. Name (i) artery R, and (ii) vein T.
3. What are tiny filters S known as?
4. Name (i) liquid U, (ii) structure V, (iii) tubes W and (iv) tube X.

What is lymphatic system? What are its functions?

Breathing cycle is an essential process for the exchange of gases’. Justify this statement.

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

There are four organisms A, B, C and D. The organism A eats only the flesh of other animals as food. The organism B can eat grains, fruits and vegetables as well as meat and fish. The organism C can make the food itself from simple inorganic substances present in the environment by utilising sunlight energy. On the other hand, organism D eats only plants and their products as food.

1. Which organism is

1. Omnivore,
2. Herbivore,
3. Carnivore?

2. Which organism is an autotroph?
3. Which organism is/ are heterotroph (s)?
4. Which organism can be a producer?
5. Which organism is/ are consumer (s)?

Give one example each of organisms which could be like A, B, C and D.

What are the different modes of nutrition? Explain with one example of each mode of nutrition.