Question

1. why is burning fossil fuels harmful to the environment?

it reduces the global average temperature.
it increases oxygen levels in the atmosphere.
it releases greenhouse gases into the air
it causes earth’s core to become hotter over time.

Explanation:

Burning fossil fuels, such as coal, oil, and natural gas, releases greenhouse gases like carbon dioxide ($CO_2$) into the atmosphere. Greenhouse gases trap heat from the sun, leading to global warming. Reducing the global average temperature is incorrect as fossil - fuel burning contributes to warming. Increasing oxygen levels is wrong because burning consumes oxygen. Causing the Earth's core to heat is not a direct effect of burning fossil fuels.

Answer:

It releases greenhouse gases into the air.