Question

Human body is made up of five important components, of which water is the main component. Food, as well as potable water, are essential for every human being. The food is obtained from plants through agriculture. Pesticides are being used extensively for a high yield in the fields. These pesticides are absorbed by the plants from the soil along with water and minerals and from the water bodies these pesticides are taken up by the aquatic animals and plants. As these chemicals are not biodegradables, they get accumulated progressively at each trophic level. The maximum concentration of these chemicals gets accumulated in our bodies and greatly affects the health of our mind and body.

1. Why is the maximum concentration of pesticides found in human beings?  (1)
2. Give one method which could be applied to reduce our intake of pesticides through food to some extent.  (1)
3. Various steps in a food chain represent:  (1) 
   1. Food web
   2. Trophic level
   3. Ecosystem
   4. Biomagnification
4. With regard to various food chains operating in an ecosystem, man is a:   (1)
   1. Consumer
   2. Producer
   3. Producer and consumer
   4. Producer and decomposer

Answer 1

1. The maximum concentration of pesticides is found in human beings because humans are at the top of the food chain and due to biomagnification, the concentration of Dichlorodiphenyltrichloroethane (DDT) increases as one goes up the trophic levels.
2. Instead of synthetic pesticides, organic farming should be done and more biopesticides should be used.
3. Trophic level
4. Consumer