The two primary factors that normally determine the level of blood pressure are:
a. the blood concentration of l-nmma and norepinephrine.
b. the cardiac output and the resistance to blood flow.
c. the blood volume and the amount of l-arginine in the diet.
d. the heart rate (heartbeats/minute) and the cardiac stroke volume.

Which of the following is a macronutrient? carbohydrates lipids amino acids all of the above

Which of the following matches the organisms described with the correct domain? a. archaea--multicellular, eukaryotic organisms that do not have cell walls b. eukarya--single-celled and multicellular organisms, with a defined nucleus and a variety of nutritional sources c. bacteria--unicellular, eukaryotic organisms with cell walls that do not contain peptidoglycan d. bacteria--unicellular, eukaryotic organisms that always lack cell walls

Which of the following is likely not involved in this example of ecological succession? a) the rotting remains of plants add to the fertility of the soil. b)the soil becomes so fertile that eel grass is replaced by other plant species. c) the roots from plants stabilize the sediment, keeping it in place. d) the concentration of salt becomes so high that all plant life is destroyed.