I need help with this is anybody available

Identify the various levels of atmosphere. troposphere mesosphere exosphere stratosphere thermosphere

How does natural selection change thephenotypes within a population over time?

Which of the following is the best definition of aerobic respiration? o a. the cellular process that releases energy by breaking down glucose o b. physical activity that involves the repeated motion of large muscle groups o c. physical activity that increases heart rate and breathing rate o d. the cellular process that converts solar energy to chemical energy