One question that scientists have not yet answered is what caused the number of large zebra mussels to decline. How might tracking different parts of the ecosystem over a long time help scientists to answer this question?

Select the correct answer. read this excerpt from leo tolstoy's the death of ivan ilyich: her attitude towards him and his diseases is still the same. just as the doctor had adopted a certain relation to his patient which he could not abandon, so had she formed one towards him—that he was not doing something he ought to do and was himself to blame, and that she reproached him lovingly for this—and she could not now change that attitude. "you see he doesn't listen to me and doesn't take his medicine at the proper time. and above all he lies in a position that is no doubt bad for him—with his legs up." she described how he made gerasim hold his legs up. the doctor smiled with a contemptuous affability that said: "what's to be done? these sick people do have foolish fancies of that kind, but we must forgive them. . " they all rose, said good-night, and went away. when they had gone it seemed to ivan ilyich that he felt better; the falsity had gone with them. but the pain remained—that same pain and that same fear that made everything monotonously alike, nothing harder and nothing easier. everything was worse. again minute followed minute and hour followed hour. everything remained the same and there was no cessation. and the inevitable end of it all became more and more terrible. based on the excerpt, how is praskovya fedorovna a character foil to ivan ilyich? a. she is kind and takes care of ivan, which is why he feels guilty about how he treated her for most of their married life. b. she is vindictive toward ivan while pretending to be worried about him, thus reminding him of how his family has never forgiven him. c. she plays the part of the worried wife without any real feeling, symbolizing the false propriety ivan upheld but now hates. d. she is young, healthy, and beautiful—everything ivan can never be again and wishes he could return to. reset next