I need help please!!

I have no idea which program you are using, but based on the information given I will say that:
Reason 1: The removal of a single species can severely impact other members of the ecosystem and change the wildlife community. Human activities, such as logging, mining, and agriculture are the most significant threat to plant and animal species.
Reason 2: More than half the medications that people use most are made from plant or animal products.
Reason 3: Millions of people visit national parks across the country each year as enjoy activities related to wildlife and nature.

If you can only use one reason per box then for reason 1 I would presume the answer to be The removal of a single species can can severely impact other members of the ecosystem and change the wildlife community.
Hope this helps!!