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प्रश्न
Explain how harmful chemicals enter our bodies.
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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 plant food, these poisonous chemical pesticides go into their bodies. Man, being an omnivore, eats plant food as well as the flesh of herbivores. Thus, the pesticides present in plant food and in the bodies of herbivores are transferred to the bodies of humans through food. In this way, harmful chemicals enter our bodies.
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संबंधित प्रश्न
Which of the following are always at the second tropic level of food chains?
In a food chain of frog, grass, insect and snake, assign trophic level to frog.
"Our food grains such as wheat and rice, the vegetables and fruits and even meat are found to contain varying amounts of pesticide residues." State the reason to explain how and why it happens?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
A food chain represents a unidirectional flow of X. What is X?
What is meant by a primary consumer, secondary consumer and a tertiary consumer? Give one example of each.
Write down a food chain in the sea.
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 |
Organisms which synthesise carbohydrates from inorganic compounds by using radiant energy are called ______.
The sea water contains water beetles, tadpole, fish and weeds.
Which organism is a secondary consumer?
A food chain occurring in the sea which provides food for many people can be written as :
phytoplankton → zooplankton → X → Y
What could be X?
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
The harmful chemical which is accumulating in human beings through food chain is :
(a) benzenehexachloride
(b) dichlorodiphenyltrichloroethane
(c) chlorofluorocarbon
(d) abscisic acid
The surface of water in a lake appears green due to a layer of tiny free-floating organisms X on its surface. The lake water also contains organisms like water beetle, fish and tadpole. The sun shines over the lake water and provides energy for the functioning of this lake ecosystem.
(a) What could organisms X be?
(b) Write a food chain comprising of all the four organisms mentioned.
(c) What is the general name of the food chains like the one written above?
(d) Name (i) secondary consumer (ii) producer (iii) tertiary consumer, and (iv) primary consumer, in the above food chain.
(e) If the tertiary consumer gets 0.2 J of energy from the secondary consumer, then how much energy was radiated by the sun to the producer?
Primary consumers that eat plants are called _______.
If 100 J energy is available at the producer level in a food chain then the energy available to the secondary consumer will be ______.
______ are organisms that are able to produce their own organic food.
Animals that eat both plants and animals are called as Carnivores.
In a food chain grasshopper gets energy by eating frog.
