instruction:
Given a scientific question, generate a correct answer to it.
question:
Name the fever that is caused by a virus that has antigens similar to molecules in human heart tissues.
answer:
rheumatic fever

question:
What do we call the diffusion of water across a membrane because of a difference in concentration?
answer:
osmosis

question:
The best thermal conductors are also the best conductors of what, which is also related to the density of free electrons in them?
answer:
electricity