Answer: C

Explanation:

Photosynthesis is a process in which plants use sunlight to produce oxygen, carbohydrates (glucose) and other nutrients by combining carbon dioxide and water. Plants take energy from the sun, carbon dioxide from the atmosphere through leaves and water from the soil through roots. Hence, statement 1 is correct.

Photosynthesis is supported by the green pigment (chlorophyll) present in the plant. Chlorophyll contains magnesium which gives the plant the ability to convert light into energy. This process can be described as follows.

Carbon dioxide + water + solar energy→ carbohydrates + oxygen

Hence, statement 2 is correct.

Answer: B

Explanation:

Photosynthesis is the basic source of life and energy for all living organisms. The oxygen produced in it is life-sustaining for humans and animals. Photosynthesis requires light and nutrients, both of which are scarce in the deep ocean. Thus, this process takes place only in the upper layers of the ocean (from the surface to a depth of about 75 meters). Hence, statement 1 is incorrect.

Sunlight does not reach the depths of the oceans, so another process takes place here which is called chemical synthesis. This process occurs around hydrothermal vents and uses chemicals instead of solar energy as an energy source. In this process, glucose and sulfur compounds are produced by green sulfur bacteria by combining hydrogen sulphide, carbon dioxide and oxygen. Hence, statement 2 is correct.

Answer: C

Explanation:

At the first level, producers are eaten by organisms, which are called primary consumers. For example, rabbits, goats etc., which eat plants, are primary consumers also called herbivores. Hence, pair 1 is correctly matched.

At the next level are secondary consumers who feed on primary consumers. For example, lions that eat deer. Hence, pair 2 is correctly matched.

At the third level are tertiary consumers who use secondary consumers as food. For example, hawks are tertiary consumers that eat snakes. Tertiary consumers can be eaten by other consumers and the chain continues. Hence, pair 3 is correctly matched.

Answer: C

Explanation:

An herbivore eats detritus, which includes organic waste, debris, and dried animal feces. Examples of detritivores are flies, cockroaches, crabs, earthworms, termites and wood ants. Both decomposers and detritivores help in the disintegration or decomposition of dead and decaying matter. Both obtain their energy from waste materials. Without their contribution the earth would be filled with dead matter and dead bodies. While herbivores actually eat the waste material, decomposers secrete enzymes to digest the waste and then absorb the released molecules. Decomposers perform another additional function as compared to herbivores. They return essential nutrients to the ecosystem. Hence, option (c) is correct.

Answer: A

Explanation:

The ecological pyramid is a graphical representation. It refers to the relationships between different living organisms at different trophic levels in an ecosystem. The shape of a pyramid can be upright (wider at the base than the top), inverted (wider at the top than the base) or variable. These are mainly of 3 types, pyramid of numbers, pyramid of biomass and pyramid of energy. The pyramid of numbers is based on the number of individuals in each trophic level. The pyramid of biomass is based on the quantitative biomass of organisms present in a unit area (standing crop) for each trophic level. The energy pyramid is based on the amount of energy available at each trophic level. Hence, statement 1 is correctly matched while statements 2 and 3 are not correctly matched.