Question

Give scientific reasons - Astronauts on the moon can not hear each other directly.

Answer 1

because there is no air on moon and air helps in the communication of voice.

Answer 2

A astronauts cannot hear themselves directly on moon as there is lack of air Particles in moons atmosphere which results in non-movement of speech molecules to travel surroundings as a result as to notes on moon or in space use radio transmitters to hear themselves.
Hope it helps⛄️