For example, if the acceleration is zero, then the velocity-time graph is a horizontal line (i.e., the slope is zero). If the acceleration is positive, then the line is an upward sloping line (i.e., the slope is positive). ... If the acceleration is great, then the line slopes up steeply (i.e., the slope is great).
Answer: Topics biologists might study at the community level of organization are cells, molecules, organisms, and populations.
