Which of the following hypotheses can be successfully tested? a. Snails were the first organisms on Earth to produce energy (ATP) through cellular respiration.
b. Plants were the first organisms on Earth to produce food (carbohydrates) through photosynthesis.
c. Cellular respiration and photosynthesis cannot occur in a closed biological system without each other.
d. Carbon dioxide is consumed by Elodea plants and produced by snails.
e. Elodea plants will increase the carbon dioxide concentration released by snails.

C would be the best answer

Explanation:

choice c,d,e can be tested although d and e are incorrect hypotheses whereas c is correct.

obviously choices a and b cannot be tested because there’s no experiment to determine wether or not an organism was the “first” to do something.

Then again all hypotheses except c are incorrect.

snails weren’t the first. Cynobacteria were the first not plants. We need both producers(autotroph plants) and consumer(heterotrophs) in a functional system and the co2 made and o2 used by heterotrophs has to be compensated for by the o2 made and co2 used in autotrophs. Elodea plants both consume and produce co2.

the correct answer is:

a population changes in response to a change in the environment.

the missing space is phylum