Answer the following question given this paragraph: Male Reproductive System Erectile dysfunction (ED) is a condition in which a man has difficulty either initiating or maintaining an erection. The combined prevalence of minimal, moderate, and complete ED is approximately 40 percent in men at age 40, and reaches nearly 70 percent by 70 years of age. In addition to aging, ED is associated with diabetes, vascular disease, psychiatric disorders, prostate disorders, the use of some drugs such as certain antidepressants, and problems with the testes resulting in low testosterone concentrations. These physical and emotional conditions can lead to interruptions in the vasodilation pathway and result in an inability to achieve an erection. Recall that the release of NO induces relaxation of the smooth muscles that surround the penile arteries, leading to the vasodilation necessary to achieve an erection. To reverse the process of vasodilation, an enzyme called phosphodiesterase (PDE) degrades a key component of the NO signaling pathway called cGMP. There are several different forms of this enzyme, and PDE type 5 is the type of PDE found in the tissues of the penis. Scientists discovered that inhibiting PDE5 increases blood flow, and allows vasodilation of the penis to occur. PDEs and the vasodilation signaling pathway are found in the vasculature in other parts of the body. In the 1990s, clinical trials of a PDE5 inhibitor called sildenafil were initiated to treat hypertension and angina pectoris (chest pain caused by poor blood flow through the heart). The trial showed that the drug was not effective at treating heart conditions, but many men experienced erection and priapism (erection lasting longer than 4 hours). Because of this, a clinical trial was started to investigate the ability of sildenafil to promote erections in men suffering from ED. In 1998, the FDA approved the drug, marketed as Viagra®️. Since approval of the drug, sildenafil and similar PDE inhibitors now generate over a billion dollars a year in sales, and are reported to be effective in treating... Q: What percentage of men suffer from some form of erectile dysfunction by age 40? Choices: - approximately 60 percent - approximately 10 percent - approximately 80 percent - approximately 40 percent A:
approximately 40 percent
Answer the following question given this paragraph: The amount of solar radiation a place receives is greatest at the Equator and lessens toward the poles. Q: What kind of radiation is greatest at the equator and lessens toward the poles? Choices: - lunar raditation - small radiation - large radiation - solar radiation A:
solar radiation
Q: Answer the following question given this paragraph: From gametogonium (plural, gametogonia ), male and female gametes develop differently - males by spermatogenesis and females by oogenesis. A gametogonium is a germ cell that divides into gametocytes during gametogenesis. Male gametogonia are called spermatogonia , and female gametogonia are called oogonia . However, the following pattern is common for both oogonia and soermatogonia (chromosome numbers depict human chromosomes):. Q: What is a germ cell that divides into gametocytes during gametogenesis? Choices: - cocklebur - gonads - pollenation - gametogonium A:
A: gametogonium
Question: Answer the following question given this paragraph: Aquatic biomes in the ocean are called marine biomes. Organisms that live in marine biomes must be adapted to the salt in the water. For example, many have organs for excreting excess salt. Marine biomes include the oceans, coral reefs, and estuaries ( Figure below ). The oceans are the largest of all the ecosystems. They can be divided into four separate zones based on the amount of sunlight. Ocean zones are also divided based on their depth and their distance from land. Each zone has a great diversity of species. Within a coral reef , the dominant organisms are corals. Corals consist partially of algae, which provide nutrients via photosynthesis. Corals also extend tentacles to obtain plankton from the water. Coral reefs include several species of microorganisms, invertebrates, fishes, sea urchins, octopuses, and sea stars. Estuaries are areas where freshwater streams or rivers merge with the ocean. Q: Aquatic biomes in the ocean are called what? Choices: - jungle biomes - arid biomes - artificial biomes - marine biomes A:
Answer: marine biomes
*Question*
Answer the following question given this paragraph: Like strong acids, strong bases can be harmful to organisms and damaging to materials. Bases have a bitter taste and feel slimy to the touch. They can also burn the skin. Bases, like acids, can be identified with litmus paper. Bases turn red litmus paper blue. Q: What color does red litmus paper turn in the presence of a base? Choices: - green - purple - white - blue A:
**Answer**
blue
Answer the following question given this paragraph: Figure 24.17 Digestive Enzymes and Hormones Enzymes in the stomach and small intestine break down proteins into amino acids. HCl in the stomach aids in proteolysis, and hormones secreted by intestinal cells direct the digestive processes. Q: Enzymes in the stomach and small intestine break down proteins into what components? Choices: - atoms - antioxidants - lactic acids - amino acids A:
amino acids