Choose the best answer.

Tracy: “I think plastic bags are not as harmful as people say. Instead, they provide great convenience.”

Nathan: “______. Plastic bags are among the biggest threats to our environment.”

What does the notice mean?

Choose the best answer.

The red squirrel in England is in danger of ______.

Choose the best answer.

The national park was established to ______ the ecosystem of the limestone forests.

Choose the best answer.

Natural resource managers ______ the needs and behaviors of wildlife.

Choose the best answer.

Scientists have been developing practical tools and methods to measure the ______ of the ecosystem.

Choose the best answer.

Naturally, many different species in this freshwater ecosystem share the same kind of ______.

Choose the best answer.

One of the factors that cause a species to become endangered is habitat ______.