Question

Study the following graph of metabolic rate of various terrestrial mamma ls as a function of their body mass and choose the correct option below.

• A. Animals are distributed throughout the curve with the smaller animals towards the left and progressively bigger animals towards the right
• B. The smaller animals below a certain critical mass cluster at the left end of the curve and the larger animals above the critical mass cluster on the right end.
• C. Animals are distributed throughout the curve with the larger animals towards the left and progressively smaller animals towards the right
• D. The larger animals above a certain critical mass cluster at the left end of the curve and the smaller animals below the critical mass cluster on the right end

Answer 1

Answer: (A)

In mammals, $BMR$ is higher per unit of body mass in small animals compared to larger ones. This is because the higher metabolic rate of small animals needs a greater delivery of oxygen to tissues around the body. Also, the smaller animals have a greater surface area to volume ratio, so more heat is lost. Thus, in the graph given animals are distributed throughout the curve with the smaller animals towards the left and progressively bigger animals towards the right.