Final answer:
Mammals had several advantages over reptiles in the dark, cold world after the asteroid impact, including endothermy, nocturnality, and diverse adaptations.
Step-by-step explanation:
Mammals had several advantages over reptiles in the dark, cold world after the impact of the asteroid. One advantage was endothermy, or the ability to regulate their own body temperature. Mammals are warm-blooded, meaning they can maintain a constant internal temperature even in colder environments, while reptiles are ectothermic and rely on external sources of heat for thermoregulation.
Another advantage mammals had was their ability to be active at night. Many mammals are nocturnal, meaning they are most active during the night when it is dark. This allowed them to exploit the resources and prey that were available in the darkness.
Lastly, mammals had a diverse range of adaptations that allowed them to survive and thrive in different environments. These adaptations included specialized teeth for different types of diets, efficient respiratory and circulatory systems, and the ability to care for their young, providing them with milk for nutrition and protection.