Question

unit 1 lesson 2 quiz
is the main cause of global warming
oxygen released into the air
contaminated water
water crisis
the release of greenhouse gases

Explanation:

Global warming is primarily caused by the enhanced greenhouse effect due to the increased release of greenhouse gases like carbon - dioxide, methane etc. into the atmosphere. Oxygen release is a normal part of the ecosystem and not a cause of warming. Contaminated water and water crisis are not the main causes of global warming.

Answer:

The release of greenhouse gases