Question

question 12 of 20 : select the best answer for the question. 12. during the carboniferous period, plants and animals grew very large due to high concentration of a. argon in the oceans. b. carbon dioxide in the oceans. c. nitrogen in the atmosphere. d. oxygen in the atmosphere. mark for review (will be highlighted on the review page)

Explanation:

During the Carboniferous period, the high atmospheric oxygen concentration (reaching around 35%) supported the growth of large plants and animals. Argon in oceans (A) and nitrogen in atmosphere (C) don't relate to organism size. Carbon dioxide in oceans (B) isn't the key factor here; high atmospheric oxygen (D) enabled efficient respiration and growth.

Answer:

D. oxygen in the atmosphere.