Answer:
.
Explanation:
To explain the last sentence, what I mean by that is the sudden decrease in air pollution in just a few weeks is what would have typically taken multiple years to do. Due to less drivers, factories shutting down, and more, less toxic and infirm mental hazardous chemicals were released into the atmosphere in an extremely short amount of time. However, nowdays, it is almost back to where is was before the pandemic.
Heat is caught in gases like methane and carbon dioxide and radiates back to earth. This causes the increase in temperature we call global warming.
It would be B. A keystone species. Keystone species play important roles in ecosystems and when they are removed this can make an entire habitat collapse
This would be describing its outward appearance.
