Answer:
carbon dioxide
Explanation:
Photosynthesis takes in the carbon dioxide produced by all breathing organisms and reintroduces oxygen into the atmosphere. Photosynthesis is the process used by plants, algae and certain bacteria to harness energy from sunlight and turn it into chemical energy.
A. He should add shells that are different colors, but the same size and type, to the tank and observe which shells the hermit crabs choose.
Durning an experiment you need to keep everything the same but only change the certain things based on your theory.
Such as how the student wanted to see if the color attracted the crab. If he had changed the size and type of the shell then the crab would have chosen the bigger one as they tend to grow into larger shells.
Yes some fishes have long tails that can be a threat which can cause fights.
Mother. red-green color blindedness is maternally inherited