Maya wrote a few steps to describe how carbon circulates between the atmosphere and living organisms. step 4 is missing.

step 1: carbon enters the atmosphere as carbon dioxide from respiration and combustion
step 2: plants use carbon dioxide to make glucose
step 3: plant-eating animals consume the glucose present in plants
step 4:

which of the following best describes step 4?

carbon dioxide in the atmosphere is used by plants for photosynthesis.

carbon dioxide in the atmosphere is converted into glucose by animals.

dead animals decompose and recycle the carbon in the form of oxygen and water.

dead animals are buried and form fossil fuels, which produce carbon dioxide when burned.

The answer is; Dead animals are buried and form fossil fuels, which produce carbon dioxide when burned.

When animals and plants are fossilized and buried under sediments, the higher pressure and temperatures turns them to oil, over time, that is mined and combusted for energy by humans. This plays a significant  role in the carbon cycle.

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.

answer: the correct option is d. enzyme

lactase and carbonic anhydrase are the examples of enzymes.

lactase is an enzyme, which is present in the small intestine of mammals. it in the digestion of the disaccharide, lactose ( milk sugar) by converting it into two monosachharide, which are glucose and galactose.

carbonic anhydrase is present in the red blood cells. this enzyme plays significant role in the transport of co₂. it in the conversion of co₂ and h₂o into carbonic acid, which is then dissociated into bicarbonate ions and hydrogen ions.