Final answer:
The enhanced jaw musculature in mammals, including the masseter and temporalis muscles, allowed for a stronger biting force and better hunting capabilities, directly contributing to the spread and diversification of mammalian species. (option a)
Step-by-step explanation:
The evolution of jaw musculature, including the masseter and temporalis muscles, provided mammals with the capability for more efficient and varied mechanisms of food processing. This development facilitated dietary expansion, which in turn aided in the survival and spread of mammals. When considering how the evolution of jaw musculature allowed mammals to spread, a more powerful biting force coupled with an enhanced ability to process a diverse array of foods emerges as a key factor.
The correct answer to the student's question, 'How did the evolution of jaw musculature allow mammals to spread?' is, therefore, option a) By enhancing biting force and better hunting. This improvement in musculature enabled mammals to become more adept hunters or foragers, allowing for the adaptation to different environments and the processing of a wider variety of foods, leading to the expansion and success of mammalian species across different habitats.
Hence, the answer is option a