How many chambers does the heart contain?
a. 3
b. 4
c. 5
d. 6

The concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important

Which of the following is not a food produced in rainforests? a) coffee b) cocoa c) avocados d) wheat

In the ocean why are the greatest amount of primary producers found in the epipelagic zone and how does that affect biodiversity