This is a practice of a workbook for the right order of paragraphs. I don't get why "however" is needed in B and what its function is logically. Does brain's giving extra time to eacape in A contradict B's physical fitness-related escape time?
A.When our ears hear a threatening sound approaching us, our brains make us believe that the source of the sound will reach us sooner than it actually will. In this way, our brains give us extra time to decide to escape if a threat is coming our way. Scientists have known this phenomenon for some time.
B.Recently, however, researchers have discussed that the length of the escape time our brains provide depends on our physical fitness. The weaker we are, the longer our escape time.
C. If we were to be threatended by approaching danger, those in weaker physical condition would rely more on escape to survive...
I think the author was using however as an equivalent of moreover, that is to say ""in addition to the phenomenon noted in A".