The passage mentions which of the following as one of the reasons why most biologists remain skeptical that chimpanzees experience a humanlike adolescent growth spurt? A. Chimpanzees do not experience a demonstrable increase in growth rate until they are fully sexually mature. B. The increase in growth rate that chimpanzees undergo at sexual maturity is less apparent than that of humans. C. The increase in growth rate once regarded as a humanlike adolescent growth spurt in chimpanzees is too sporadic to be regarded as significant. D. Not all chimpanzees undergo a calculable growth spurt. E. Watt's approach to analyzing data is considered to be highly unorthodox.