Question

Kai has a see-through glass tank with air, plants, and animals that eat those plants. He sealed the tank so no material can get into or out of it, but light can get in when the tank is not covered.
The light for the tank has been on all day, and Kai measured the carbon in the air and found that it is decreasing. How is carbon moving between the air and the living things in the tank? What is happening to the amount of carbon in living things? Explain your thinking as completely as possible.

Answer 1

Answer:

1. Carbon is moving from the living things in the tank into the air when they respirate, and from the air back into plants via photosynthesis

2. The amount of carbon in living things is increasing as plants use the carbon in the atmosphere, and animals eat the plants.

Explanation:

According to the question, a well sealed tank contains air, plants and animals. Since light can get into the tank, plants can perform photosynthesis. Living things in the tank release carbon in form of carbondioxide (CO2) gas through respiration. Plants then make use of this carbondioxide (CO2) to synthesize carbon-containing food (glucose) in the presence of sunlight. This process is called PHOTOSYNTHESIS.

Animals eat those plants and the stored carbon in the plants gets transferred to them. The animals release this carbon into the air again in the form of carbondioxide when they respire. Hence, carbon in the tank moves from the living things (respiration) into the air and back into plants (photosynthesis).

2. Since the amount of carbon in the air is decreasing, the carbon is being used by the living things in the tank. Plants absorb the carbon in the atmosphere for photosynthesis, then animals eat the plants to get the carbon. Therefore, the amount of carbon in the living things is increasing.