Ihave collected so large a body of with animals and plants a cross between different varieties, or between individuals of the same variety but of another strain, gives vigour and fertility to the offspring; and on the other hand, that close interbreeding diminishes vigour and fertility; that these facts alone incline me to believe that it is a general law of nature that no organic being fertilizes itself for a perpetuity of generations; but that a cross with another individual is occasionally—-perhaps at long intervals of time—indispensable. in this sentence from the third paragraph of the passage, what does perpetuity mean? a) gratefulness b) consideration c) a temporary state d) time without end; eternity

Part a which statement best describes a central idea in this narrative? in times of tragedy, it is difficult to determine how best to be of service. in times of crisis, people prefer to be alone. young people tend to look to older people to take action in times of tragedy. when people publicly commit to being of service, they are more likely to follow through. part b which detail from the text best to shape the central idea in part a? "'i thought you might have too much going on already. i saw everyone post online.' martin said, 'i don’t think anyone wanted to be in the way today, so i’m glad you came.'" "finally, he said, 'i don’t know what to do. i guess i should tell him to let me know if he needs anything, but that doesn’t feel like enough.'" "he wondered how many people would actually show up to out and how many would simply hope that enough others did." "he explained to her that martin’s mom had died, and told her how he felt about his friend’s loss. 'what do you plan to do for him? ' his mother asked."