Mammals do; I'm in my science class
A the concentration gradient!
<em><u>The area inhabited by a population is known as its</u></em><em><u> </u></em><em><u>geographic distribution.</u></em>
<em><u>have</u></em><em><u> </u></em><em><u>a</u></em><em><u> </u></em><em><u>great</u></em><em><u> </u></em><em><u>day</u></em><em><u>!</u></em>