Which is a characteristic of dark matter

Question

It interacts with electromagnetic radiation
It has not been observed directly
It does not interact with baryonic matter
Humans can see it

Answer 1

A characteristic of dark matter is:

It has not been observed directly.

Dark matter does not interact with electromagnetic radiation, which is why it is "dark" and cannot be seen with traditional telescopes. It is thought to interact with baryonic matter only through gravity, and humans cannot see it because it doesn't emit, absorb, or reflect light.