What does pollution mainly come from

Pollution comes from factories, careless humans, chemicals, non-biodegradable trash.

Explanation:

mobile sources – such as cars, buses, planes, trucks, and trains.

Explanation:

practical process described pest part of scientific investigation.

because practical knowledge is powerful then therotical knowledge.

i don't see a text, but i am gonna assume this *orbit* the curved path, usually elliptical, described by a planet, satellite, spaceship, etc., around a celestial body, as the sun.