State one reason to justify the position of man at the apex of most food chains.

If a harmful chemical enters a food chain comprising snakes, hawks, mice and plants, which of these organisms is likely to have maximum concentration of the harmful chemicals in its body?

Name the organisms belonging to the second and fourth trophic levels in the food chain comprising the following:

Frogs, Plants, Snakes, Hawks, Insects.

What are the functions of an ecosystem?

Give proper term for each of the following:

(a) Smaller constituent operational unit of biosphere.

(b) Accumulation of non-biodegradable toxic substance in the increasing order in a food chain.

Which layer is found above ozone layer of the atmosphere? Mention one characteristic feature of this layer.

Why do harmful chemicals concentrate as we go up in a food chain?

With the knowledge of energy transfer in the food chain, man can place himself at an advantageous position in the food chain. Explain.

A food chain consists of the following members. If the last member receives 30 J of energy, make a diagrammatic representation to show the flow of energy.

Snake, Vulture, Plants and Rat.

Describe with a diagram how energy flows through different trophic levels. Describe how transfer and circulation of material takes place in nature, and the role of decomposers in the process. State how recycling of materials benefits living organisms.

With the help of examples discuss in brief the role of decomposers in cycling of materials.

Consider the following food chains:

(a) Plants → Mice → Snakes → Hawks

(b) Plants → Mice → Hawks

If energy available at the producer level in both the food chains is 100 J, in which case will hawks get more energy as food and by what factor? Justify your answer.

What are chlorofluorocarbons? How are they responsible for causing ozone hole in atmosphere? What will be the consequence of ozone hole?

Ayush went to Puri in Orissa on a holiday recently. There are lots of tourists on the beach and the beach was very dirty with plastic, paper, waste food, mineral water bottle, etc. Ayush decided to do something to save the beach.

(a) What can Ayush do to save the beach from becoming a dumping ground?

(b) How can government help in keeping the beach clean?