Suppose that another scientist writes a rebuttal to the findings presented in Investigating Life 26.1. The scientist suggests that a mutation in the myosin gene is unlikely to be the cause of smaller jaw muscles. The scientist proposes that it is much more likely that the first human ate softer food and therefore did not exert the jaw muscles, so they became smaller. These smaller jaw muscles were then passed on to offspring. What is the most appropriate response to this alternative proposal