17. The scientific study of human populations is called A. ecology
B. demography
C. natural selection.
D. transition.

Describe the response the kidneys have to dehydration and excessive water intake. what happens to the concentration of urine in each case ?

Cpr, or cardiopulmonary resuscitation, is a first-aid technique to save lives. it involves compressions of the patient's chest cavity. which description is the best description of the functions of chest compressions in cpr? chest compressions are done to pump the heart. chest compressions are done to strengthen the rib bones. chest compressions increase carbon dioxide inhalation. chest compressions allow the patient's muscles to wake up.

What is the most abundant vertebrate on earth?