What is the primary muscle used for normal breathing and which additional muscles are used to increase inspiration and expiration when performing strenuous exercise?

Cell engulfs molecules in cell "drinking":

Which of the following statements is true of evolution? A. Evolution does not always progress in one set direction. B. Earth's present-day species evolved from older, identical species. C. Limited resources discourage the evolution of species. D.

For what is the cherokee leader sequoyah remembered?

Which of the following is a situation that could lead to the extinction of a species? A increased food supply B increased habitat C increased competition D increased population size

Can someone explain the carbon cycle to me as in how it's important in the real world?

How does a muti-celluar organisms organise

Is the cell wall or cell membrane composed of two layers of lipids and proteins?

What kind of cells is an amoeba?

What happens when you get scared "Half to death twice"?

Atoms of different elements combine to form