(Q).
Answer the following question given this paragraph: Veins are blood vessels that carry blood toward the heart. This blood is no longer under pressure, so veins have thinner walls. To keep the blood moving, many veins have valves that prevent the backflow of blood. Veins generally carry oxygen-poor blood. The smallest veins are called venules. They merge to form larger and larger veins. The largest vein is the inferior vena cava, which carries blood from the lower body directly to the heart. Q: What are the blood vessels that carry blood toward the heart and tend to have thinner walls? Choices: - capillaries - glands - clots - veins A:
(A).
veins

(Q).
Answer the following question given this paragraph: First, notice where carbon is fixed by the enzyme Rubisco. In C-3, C-4, and CAM plants, CO 2 enters the cycle by joining with 5-carbon ribulose bisphosphate to form a 6-carbon intermediate, which splits (so quickly that it isn't even shown) into two 3-carbon 3-phosphoglycerate molecules. Now look for the points at which ATP and NADPH (made in the light reactions) add chemical energy ("Reduction" in the diagram) to the 3-carbon molecules. The resulting glyceraldehyde-3-phosphate "half-sugars" can enter several different metabolic pathways. One recreates the original 5-carbon precursor, completing the cycle. A second combines two of the 3-carbon molecules to form glucose, the universal fuel for life. The cycle begins and ends with the same 5-carbon RuBP molecule, but the process combines carbon and energy to build carbohydrates food for life. Q: What elements do mafic minerals typically include? Choices: - iodine and magnesium - sodium and magnesium - xerophyte and magnesium - iron and magnesium A:
(A).
iron and magnesium

(Q).
Answer the following question given this paragraph: Proteins Function as Enzymes If you were trying to type a paper, and every time you hit a key on your laptop there was a delay of six or seven minutes before you got a response, you would probably get a new laptop. In a similar way, without enzymes to catalyze chemical reactions, the human body would be nonfunctional. It functions only because enzymes function. Enzymatic reactionschemical reactions catalyzed by enzymesbegin when substrates bind to the enzyme. A substrate is a reactant in an enzymatic reaction. This occurs on regions of the enzyme known as active sites (Figure 2.27). Any given enzyme catalyzes just one type of chemical reaction. This characteristic, called specificity, is due to the fact that a substrate with a particular shape and electrical charge can bind only to an active site corresponding to that substrate. Q: What is the name of a reactant in an enzymatic reaction? Choices: - membrane - Scar - tissues - substrate A:
(A).
substrate