Question

the study of the structuresvof deep-sea vents and of the life around them represents an intersection of which two fields of science

Answer 1

It's probably either of Geology and Oceanography.

Geology is the study of solid earth which deals on rocks while Oceanography simply studies the ocean. For the study of deep-sea vents, it's probably more into geology while the studies of life on the deep sea is part of oceanography.