Answer:
Option B
Step-by-step explanation:
Gas exchange occurs through the skin of the frogs. The rate of gas exchange depends on several factors such as
A) Surface area
B) Thickness of the medium
C) Difference in the concentration of the gas across the skin/surface
Of the two give options, the bull frog has larger body as compared to that of dart frog hence; its surface area will be larger among the two frog species. With larger surface area it will have higher gas exchange.
Hence, option B is correct