Define greenhouse effect. Describe which gases are important to the greenhouse effect.

Define greenhouse effect. Describe which gases are important to the greenhouse effect.
What were listed as human activities related to greenhouse gas production from each link?
How do humans contribute to both climate change and major extinction events?
Some scientists think that human activities may be contributing to a sixth mass extinction event. What specific evidence do they site for this possible event? (you may need to conduct additional research to support your findings).