The large size of insects and amphibians during the Pennsylvanian period has been suggested to be due to ________.
A)a lack of predators for early land forms
B)an excess of sunlight and water during that time
C)an excess of oxygen during that time
D)a decrease in methane in the atmosphere during that time
E)the emergence of a super continent that allowed greater areas for animals to evolve

Question

Quizplus · Accepted Answer

The large size of insects and amphibians during the Pennsylvanian period has been suggested to be due to an excess of oxygen during that time. Fossil evidence indicates that atmospheric oxygen levels during the Pennsylvanian period were as high as 35%, compared to the current 21%. This allowed for greater oxygen diffusion in large bodies, enabling larger body sizes.

The Large Size of Insects and Amphibians During the Pennsylvanian