Question

Why energy flow is called a "one way Street"?
(class 10 CBSE SAMPLE PAPER 2017-18 SCIENCE)

Answer 1

SOLUTION:
Energy flow is called a “one way street” because energy always flows in one direction in a food chain from sun to the producers (autotrophs) and then to various categories of consumers (heterotrophs). Energy never flows  in the other direction. Hence the energy trapped by the producer does not revert  to the sun and energy passed on to the herbivores cannot be returned to the producers.

For example the transfer of energy takes place from grass to deer and then to lion it cannot take place in the reverse direction from lion to deer to grass.

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