Valves are present in between the auricles and ventricles of the heart. Give one reason.

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.

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?

Explain the principle of dialysis with the help of a labelled diagram.

Differentiate between an autotroph and a heterotroph.

The transport system in plants consists of two kinds of tissues X and Y. The tissue X is made up of living cells and consists of two components A and B. The component A has tiny pores in its end walls and contains only cytoplasm but no nucleus. On the other hand, component B has cytoplasm as well as nucleus. The tissue Y is made up of dead cells and consists of two components C and D. The component C has open ends whereas component D does not have open ends. In flowering plants, either only C or both C and D transport water but D is the only water conducting tissue in non - flowering plants.

1. What is (i) tissue X, (ii) component A and (iii) component B?
2. What is (i) tissue Y, (ii) component C and (iii) component D?

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?

Name the main organs of the human digestive system in the order they participate in the process of digestion. Describe how digestion of carbohydrates and proteins take place in our body.

1. Draw the structure of a nephron and label the following on it: Glomerulus, Bowman’s capsule, Renal artery, Collecting duct.
2. What happens to glucose that enters the nephron along with filtrate?

What are the methods used by plants to get rid of their waste products?