Studies of ——- among turtles are sometimes ——- by
the fact that the subjects live so long that researchers
retire before the studies can be completed.
(A) extinction . . enhanced
(B) longevity . . hampered
(C) behavior . . belied
(D) mortality . . bolstered
(E) reproduction . . confirmed
Other meanings are available here:
What is a turtle scientist called?
What is a researcher called?
What exactly do researchers do?