A scientist places a mouse in a sealed, transparent container with a sensor to measure gas concentrations. Which change would be the most direct evidence of the mouse's respiration?

A steady decrease in the concentration of nitrogen gas.

A steady increase in the concentration of oxygen gas.

A steady increase in the concentration of carbon dioxide gas.

A complete stabilization of all gas levels within the container.

Which statement best contrasts the roles of photosynthesis and respiration in the carbon cycle?

Respiration removes carbon dioxide from the atmosphere, while photosynthesis releases it.

Photosynthesis captures atmospheric carbon in organic molecules, while respiration releases it.

Both processes are performed only by animals to cycle carbon through the food web.

Photosynthesis transfers carbon from the soil to the air, while respiration moves it from the air to the soil.

From an abiotic source to another abiotic source.

From a biotic source to another biotic source.

From an abiotic source to a biotic source.

From a biotic source to an abiotic source.