Question

read the following introductory paragraph:
a slow, sad drama unfolding on a remote island is providing a grim challenge to the national park services traditional policy of letting nature take its course. isle royale in lake superior is home to the longest studied predator - prey relationship in the world. for over sixty years biologists have been watching the islands moose and wolf populations, recording but not interfering in their struggles. but now, the wolf population is doomed and the delicate island ecosystem is spinning out of balance. it is time for nps scientists to put down their notebooks and step in. it is time to save the wolves, and save the island.
what is the main function of the sentence “it is time for nps scientists to put down their notebooks and step in,” in the paragraph?
it helps set the tone.
it presents the thesis.
it introduces the topic / provides background information.
it hooks the reader.

Explanation:

• "It helps set the tone": Setting tone involves creating an emotional atmosphere, but this sentence is about a call to action, not tone-setting.
• "It presents the thesis": The thesis of the paragraph (the main argument) is that NPS scientists should intervene to save the wolves and the island. This sentence directly states the call to action that is the core argument, presenting the thesis.
• "It introduces the topic / provides background information": The topic (Isle Royale's ecosystem) and background (moose - wolf study) are introduced earlier; this sentence is a conclusion - like call to action, not introduction/background.
• "It hooks the reader": Hooking the reader is done at the start (e.g., the "slow, sad drama" part), not by this call - to - action sentence.

Answer:

B. It presents the thesis.