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प्रश्न
'If we excessively use pesticides to protect the crops from diseases, then it may cause long-term damage to mankind'. Justify this statement.
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उत्तर
Chemical substances such as pesticides are sprayed over crop plants to protect them from pests and diseases. When herbivorous animals eat the plant food, these poisonous chemical pesticides go into their bodies. Man, being an omnivore, eats plant food as well as the meat of herbivores. Thus, the pesticides present in plant food and herbivores get transferred to man's body through food. Pesticides are non-biodegradable chemicals, so they get accumulated at each trophic level. Since humans occupy the top level in any food chain, the maximum amount of harmful chemical pesticides gets accumulated in our bodies, damaging our health gradually.
Hence the statement 'excessive use of pesticides to protect crops from diseases may cause long-term damage to mankind' is justified.
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संबंधित प्रश्न
List two main components of ecosystem?
Which of the following constitute a food-chain?
In the following food chain, 20,000 J of energy was available to the plants. How much energy would be available to man in this chain?
Plants → Sheep → Man
The following statement is true or false :
Secondary consumers and tertiary consumers, both are carnivores.
Which organisms belong to third and fourth trophic levels in the food chain comprising the following?
Rats, Plants, Hawk, Snakes
Write down a food chain in the sea.
At which trophic level a person is feeding when he is eating bread.
Which of the following represents a possible food chain found in a pond :
| Primary producers |
Primary consumers | Secondary consumers |
| (a) green algae | fish | mosquito larvae |
| (b) fish | green algae | mosquito larvae |
| (c) mosquito larvae | fish | green algae |
| (d) green algae | mosquito larvae | fish |
Which of the following statement is incorrect?
A food chain occurring in the sea which provides food for many people can be written as :
phytoplankton → zooplankton → X → Y
Name two zooplanktons.
A food chain occurring in the sea which provides food for many people can be written as :
phytoplankton → zooplankton → X → Y
Which organism in the above food chain is a (1) primary consumer, and (2) tertiary consumer?
What percentage of sun's energy falling on the leaves of green plants is utilised by the plants in the process of photosynthesis and stored as chemical energy of food?
(a) 99 per cent
(b) 10 per cent
(c) 1 per cent
(d) 20 per cent
In addition to wheat plants, a crop field ecosystem has organisms such as snake, peacock, eagle and mice. If the wheat plants are sprayed with pesticides periodically, which of the following will have the minimum concentration of pesticides in the body?
(a) snake
(b) eagle
(c) mice
(d) peacock
Green plants utilize ______ percent of sun’s energy to prepare their food by the process of photosynthesis.
The sequence of who eats whom in an ecosystem is called as ______.
Define – Heterotrophs.
DDT was sprayed in a lake to regulate breeding of mosquitoes. How would it affect the trophic levels in the following food chain associated with a lake? Justify your answer.
If a harmful chemical enters a food chain comprising peacocks, plants, rats and snakes, which of these organisms is likely to have the highest concentration of the chemical in its body? Justify your answer. Name the process involved and define it.
Use of several pesticides which results in excessive accumulation of pesticides in rivers of ponds, is a matter of deep concern. Justify this statement.
