system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What do they do on the ISS? What significant contributions have they made to science?
gpt
The astronauts aboard the ISS are constantly running experiments, mostly on the effects of zero-g on various lifeforms. Interesting things to note, can plants be grown in space, do certain germs or bacteria grow faster or slower in space, and so on.