why thermophiles trive at high temperatures and cannot survive well at lower temperatures?
They evolved in high temperatures and thus are now obligate thermophiles.
Biologists in microprop you say??  Well, it depends.  THere are several stages and a biologist could be responsible for any part of them.  For instance, making the callus culture and ensuring that the proper amount of plant horomones are present, to the actual studying of methods of microprop. Quality control, disease checking, all that jazz. If you want specifics, that's a lot of information but you could look up wikipedia.org, and I am sure they have anice section on microprop.  Good luck!