Answer:
The return of blood to the heart is assisted by the action of the skeletal- muscle pump. As muscles move, they squeeze the veins running through them. Veins contain a series of one-way valves, and they are squeezed, blood is pushed through the valves, which then close to prevent backflow.
Antagonistic is the term for the phenomenon that occurs when two hormones present together to produce effects that are weaker than the effects of either one acting alone.
An antagonism, in ecology is an association between the organisms in which one benefits at the expense of the other. In Biology, it can be defined as A biological response to the exposure to multiple substances which is very less than would be predicted if the known effects of the individual substances were added together. For example, Your little sister or brother benefiting by disturbing you while you study.
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B. The flower color in a population changes over time.
The pelvis is different in males vs. females, particularly the sub-pubic angle.
