If adequate nutrients are present, primary productivity depends on . a. organism size
b. salinity
c. temperature
d. illumination
e. organism density

What are some natural processes that represent physical and chemical changes?

How are fossils used to date organisms?

Which of the following is one way in which organisms such as clown fish and sea turtles are able to overcome the many dangers that their offspring encounter and ensure that their species population numbers stay relatively steady