Read this excerpt from "A Student's Guide to Global Climate Change." As the Earth gets warmer, plants and animals that need to live in cold places, like on mountaintops or in the Arctic, might not have a suitable place to live. If the Earth keeps getting warmer, up to one-fourth of all the plants and animals on Earth could become extinct within 100 years. Every plant and animal plays a role in the ecosystem (for example, as a source of food, a predator, a pollinator, a source of shelter), so losing one species can affect many others.

What can people do about it?
Just like people, plants and animals will have to adapt to climate change. Many types of birds in North America are already migrating further north as the temperature warms. People can help these animals adapt by protecting and preserving their habitats.

Based on the excerpt, what conclusion can be drawn about endangered species?

Humans cannot help species that are already endangered.
Humans cannot protect the habitats of endangered species.
Humans can solve all problems that endangered species face.
Humans can help endangered species adjust to new environments.