Question

the younger dryas was a period of extreme cooling from 11,700 to 12,900 years ago in the northern hemisphere. some scientists argue that a comet fragment hitting earth brought about the cooling. others disagree, partly because there is no known crater from such an impact that dates to the beginning of the period. in 2015, a team led by kurt kjær detected a 19 - mile wide crater beneath a glacier in greenland. the scientists who believe an impact caused the younger dryas claim that this discovery supports their view. however, kjærs team hasnt yet been able to determine the age of the crater. therefore, the team suggests that____ 14 mark for review which choice most logically completes the text? a it cant be concluded that the impact that made the crater was connected to the beginning of the younger dryas. b it cant be determined whether a comet fragment could make a crater as large as 19 miles wide. c scientists have ignored the possibility that something other than a comet fragment could have made the crater. d the scientists who believe an impact caused the younger dryas have made incorrect assumptions about when the period began.

Explanation:

The key - point is that the age of the newly - discovered crater cannot be determined yet. Scientists who think an impact caused the Younger Dryas claim the discovery supports their view, but without knowing the crater's age, it can't be concluded that the impact was related to the start of the Younger Dryas.

Answer:

A. It can't be concluded that the impact that made the crater was connected to the beginning of the Younger Dryas.