What is the purpose of the first sentence of a paragraph?

to provide an introduction
to state the main idea
to give a transition
to change the focus

1point for this topic sentence, what would not be a good concluding sentence for the paragraph? topic sentence: the u.s. government's resistance to put polar bears on the list of endangered species has allowed for the continued decrease of the already threatened population. o a. any more delay will surely result in the continued loss of polar bear populations. o b. i saw a polar bear in a zoo, and it looked sad to not be in the wild o c. without swift action, polar bears may soon be extinct in the wild. o d. any of these would be a good concluding sentence,