Carbon is found in all living organisms. The constant flow of carbon on Earth through organisms and the air is
known as the carbon cycle. absorb carbon from the atmosphere in the form of carbon
dioxide. They use it for respiration and . Animals consume plants, transferring carbon
along the food chain. Plants and animals respire and release carbon into air. When the animals and plants
die, they are eaten by . Carbon enters back into the atmosphere in the form of
.

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

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