A vein is a blood vessel that always carries
(a) blood toward the heart.
(b) blood away from the heart.
(c) oxygen-rich blood.
(d) oxygen-poor blood.
(a) blood toward the heart
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The clonal selection theory is an explanation for
A. how a single type of stem cell can produce both red blood cells and white blood cells. B. how antibody proteins can be molded to fit antigens after the antigen interacts with the antibody-producing type of cell. C. how an antigen can induce the multiplication of very few cells to result in production of high levels of specific antibodies. D. how HIV can disrupt the immune system. E. how macrophages can recognize specific T cells and B cells.
Archeons that can survive at very warm temperatures are: a. bacteriorhodopsins
b. hyperthermophobes. c. hypothermophiles. d. hyperthermophiles.
In general, when would the net movement of small, uncharged atoms and molecules through the plasma membrane end?
A) when the concentration of a solute is equal on both sides of the membrane B) when all of those atoms or molecules are on the same side of the membrane C) when the cell grows so large that it can't hold any more material D) when the cell shrinks to the point that it can't function properly
Which of the following protist lineages does NOT belong to the supergroup Excavata?
a. Kinetoplastids b. Parabasalids c. Diplomonadas d. Diatoms