Problem:OPTIONS:
- reproduction
- metabolism
- photosynthesis
- respiration

Answer the following question given this paragraph: Internal Respiration Internal respiration is gas exchange that occurs at the level of body tissues (Figure 22.23). Similar to external respiration, internal respiration also occurs as simple diffusion due to a partial pressure gradient. However, the partial pressure gradients are opposite of those present at the respiratory membrane. The partial pressure of oxygen in tissues is low, about 40 mm Hg, because oxygen is continuously used for cellular respiration. In contrast, the partial pressure of oxygen in the blood is about 100 mm Hg. This creates a pressure gradient that causes oxygen to dissociate from hemoglobin, diffuse out of the blood, cross the interstitial space, and enter the tissue. Hemoglobin that has little oxygen bound to it loses much of its brightness, so that blood returning to the heart is more burgundy in color. Considering that cellular respiration continuously produces carbon dioxide, the partial pressure of carbon dioxide is lower in the blood than it is in the tissue, causing carbon dioxide to diffuse out of the tissue, cross the interstitial fluid, and enter the blood. It is then carried back to the lungs either bound to hemoglobin, dissolved in plasma, or in a converted form. By the time blood returns to the heart, the partial pressure of oxygen has returned to about 40 mm Hg, and the partial pressure. Q: Internal and external forms of what life process occur as simple diffusion due to a partial pressure gradient? A:
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A: respiration

Problem:OPTIONS:
- electrical cascades
- spontaneous cascades
- mutation cascades
- enzymatic cascades

Answer the following question given this paragraph: The effects of extracellular signals can also be amplified by enzymatic cascades. At the initiation of the signal, a single ligand binds to a single receptor. However, activation of a receptor-linked enzyme can activate many copies of a component of the signaling cascade, which amplifies the signal. Q: What helps amplify the effects of extracellular signals? A:
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A: enzymatic cascades

Problem:OPTIONS:
- testicle
- clitoris
- pelvic brim
- the uterus

Answer the following question given this paragraph: The vagina is a tube-like structure about 9 centimeters (3.5 inches) long. It begins at the vulva and extends upward to the uterus. It has muscular walls lined with mucous membranes. The vagina has two major reproductive functions. It receives sperm during sexual intercourse, and it provides a passageway for a baby to leave the mother's body during birth. Q: The vagina starts at the vulva and ends where? A:
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A: the uterus

Problem:OPTIONS:
- noble gases
- the acid group
- metalloids
- the oxygen group

Answer the following question given this paragraph: Group 16 is called the oxygen group. The first three elements in this group are nonmetals. They are followed by one metalloid and one metal. All the elements in the oxygen group have six valence electrons, and all are reactive. Oxygen (O), for example, readily reacts with metals to form compounds such as rust. Oxygen is a gas at room temperature. The other four elements in group 16 are solids. Q: Group 16 is called what? A:
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A:
the oxygen group