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प्रश्न
The harmful chemical which is accumulating in human beings through food chain is :
(a) benzenehexachloride
(b) dichlorodiphenyltrichloroethane
(c) chlorofluorocarbon
(d) abscisic acid
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उत्तर
dichlorodiphenyltrichloroethane
The harmful pesticide that accumulates in the bodies of human beings through the food chain, through a process known as biomagnification, is dichlorodiphenyltrichloroethane (DDT).
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संबंधित प्रश्न
List two important roles play in the environment by decomposers.
Will the impact of removing all the organisms in a trophic level be different for different trophic levels? Can the organisms of any trophic level be removed without causing any damage to the ecosystem?
What are planktons?
Which category of organisms forms the starting point of a food chain?
In a food chain, the initial organism is usually :
(a) photosynthetic
(b) herbivore
(c) saprophytic
(d) parasitic
Which of the following are decomposers of dead organisms?
| Bacteria | Fungi | Viruses |
| (a) no | yes | yes |
| (b) yes | no | yes |
| (c) yes | yes | no |
| (d) yes | yes | yes |
A food chain occurring in the sea which provides food for many people can be written as :
phytoplankton → zooplankton → X → Y
Name two zooplanktons.
If 5 joules of energy is available at producer level (plants), then how much energy will be transferred to the lion in the following food chain?
Plants → Goat → Lion
Fill in the following blank with suitable word :
Plants → Antelope → ............
What is ten per cent law? Explain with an example.
Explain why, the flow of energy in the ecosystem is said to be unidirectional.
Consider the following food chain
(i) Plants → Mice → Snakes → Hawks
(ii) 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 how much? Justify your answer.:
Explain why, a food chain usually cannot have more than three or four steps.
Which of the following limits the number of trophic levels in a food chain?
(a) insufficient food supply from producer level
(b) decrease in energy at higher trophic levels
(c) increase in the number of organisms at higher trophic levels
(d) accumulation of harmful chemicals at higher trophic levels
A food chain consists of fish, larvae, phytoplanktons and birds. The level of pesticides in water in which the fish, larvae and phytoplanktons live is quite high.
Write the food chain comprising all the organisms mentioned above.
"Energy flow in food chains is always unidirectional". Justify this statement. Explain how the pesticides enter a food chain and subsequently get into our body.
| 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. |
- Why is the maximum concentration of pesticides found in human beings? (1)
- Give one method which could be applied to reduce our intake of pesticides through food to some extent. (1)
- Various steps in a food chain represent: (1)
- Food web
- Trophic level
- Ecosystem
- Biomagnification
- With regard to various food chains operating in an ecosystem, man is a: (1)
- Consumer
- Producer
- Producer and consumer
- Producer and decomposer
What would happen if an organism is removed from the food chain?
Differentiate between herbivores and carnivores.
