The bees' tendency to sacrifice themselves for the clan (I) ________ biologists operating under the assumption that all organisms behave out of (ii) _______ .

So I am unaware about the first blank correct word in this question but still could solve it. Below is the strategy that I used. Focus on the highlighted parts, so the second blank if we see the options needs to be opposite of "sacrifice" ( -ve ) word and the first blank is basically not validating biologists hypothesis.

Answers : Flummoxed, Self interest