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प्रश्न
Your mother always thought that fruit juices are very healthy for everyone. One day she read in the newspaper that some brands of fruit juices in the market have been found to contain certain level of pesticides in them. She got worried as pesticides are injurious to our health.
(a) How would you explain to your mother about fruit juices getting contaminated with pesticides?
(b) It is said that when these harmful pesticides enter our body as well as in the bodies of other organisms they get accumulated and beyond a limit cause harm and damage to our organs. Name the phenomenon and write about it.
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उत्तर
(a) The pesticides are commonly used to kill the pests in crop fields. However, these pesticides contain several non-biodegradable chemicals, that can stick to the surface of the fruits, vegetables and other plant parts. If these fruits are not washed properly before use, these chemicals remain attached to them and thus can contaminate the fruit juices.
(b) A large number of pesticides and chemicals are used to protect our crops from pests and diseases. Some of these chemicals are washed down into the soil, while some enter into the water bodies. From the soil, they are absorbed by plants along with water and minerals, and from water bodies, they are taken up by aquatic plants and animals. This is how these chemicals enter the food chain. Because these chemicals cannot decompose, they accumulate progressively at each trophic level. As the food chain proceeds, the concentration of pesticides also increases. This increase in the concentration of harmful chemicals with each step of the food chain is called biomagnification.
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संबंधित प्रश्न
Why are plants called producers?
What is meant by a primary consumer, secondary consumer and a tertiary consumer? Give one example of each.
At which trophic level a person is feeding when he is eating bread.
The sea water contains water beetles, tadpole, fish and weeds.
Write a food chain comprising all the given organisms.
The following is a food chain that ends with human :
How does this food chain differ form a usual food chain involving human such as : plants → goat → human?
Explain how harmful chemicals enter our bodies.
Explain why, the flow of energy in the ecosystem is said to be unidirectional.
A food chain comprises of cat, seed-eating bird, plants, and dog. The organism which will have the maximum concentration of harmful pesticides coming through the food chain is most likely to be :
(a) cat
(b) plants
(c) dog
(d) seed-eating bird
Bacteria and fungi are called decomposers.
______ obtained energy from the chemical breakdown of dead organisms.
