Which of the following might cause chronic hemorrhagic anemia?
a) iron deficiency in the diet
b) decreased epo production
c) a bleeding ulcer
d) sickle-cell anemia

Molecular models of two different substances are shown below. in the molecule on the left, the oxygen atom pulls on electrons more strongly than the hydrogen atoms. in the molecule on the right, the two oxygen atoms pull on the shared electrons with the same strength. water molecule, h,o oxygen molecule, oz when the two substances are put in the same container, they do not attract each other. why does this happen? a. they both contain oxygen. b. one is polar and one is nonpolar. c . they are both polar. d. they contain different elements.

The concept of keystone species is controversial among ecologists because most organisms are highly interdependent. if each of the trophic levels is dependant on all others how can we say one is most important

Which of the following is the source of energy for photosynthesis? a.) glucose b.) chlorophyll c.) carbon dioxide d.) sunlight