Which sentence effectively summarizes the main point of the paragraph about hunters?

The sentence that effectively summarizes the main point of the paragraph about hunters is the one stating that human hunters frighten wildlife. This option encapsulates the overall impact that hunters have on animal behavior, indicating a change in the animals' natural state due to the presence of humans. It emphasizes the interaction and dynamic between hunters and wildlife, highlighting a significant consequence of hunting – the fear that it instills in animals.

In contrast, while different animals reacting to humans points to a variety of behaviors, it does not clearly communicate the primary focus on hunters' influence. The statement about hunting being an ancient practice provides historical context, but it does not address the immediate effects on wildlife. Similarly, the caution of birds compared to mammals adds detail about specific animal reactions without summarizing the paragraph’s main point regarding the relationship between hunters and wildlife broadly.