Answer the following question given this paragraph: Bradykinin is a peptide hormone composed of nine amino acids that lowers blood pressure. Its primary structure is arg-pro-pro-gly-phe-ser-pro-phe-arg. Would you expect bradykinin to be positively charged, negatively charged, or neutral at a pH of 6.0? Justify your answer. Q: What do we call a peptide hormone composed of nine amino acids that lowers blood pressure? Choices: - angiotensin - parcnid - bufotenin - bradykinin A:
bradykinin
Answer the following question given this paragraph: In some countries, birth rates have fallen even lower than death rates. As result, their population growth rates are negative. In other words, the populations are shrinking in size. These populations have top-heavy population pyramids, like the one for Italy shown in Figure below . This is a new stage of the demographic transition, referred to as Stage 5. You might think that a negative growth rate would be a good thing. In fact, it may cause problems. For example, growth-dependent industries decline. Supporting the large aging population is also a burden for the shrinking younger population of workers. Q: What results when birth rates fall even lower than death rates? Choices: - disease - mutation - increased growth rate - negative growth rate A:
negative growth rate
Q: Answer the following question given this paragraph: Metamorphism changes rocks by heat and pressure. These agents create an entirely new type of rock. Metamorphism changes rocks physically and/or chemically. Q: Which process changes rocks by heat and pressure? Choices: - sediments - Changes - weathering - metamorphism A:
A: metamorphism
Question: Answer the following question given this paragraph: Why is activation energy needed? A reaction won't occur unless atoms or molecules of reactants come together. This happens only if the particles are moving, and movement takes energy. Often, reactants have to overcome forces that push them apart. This takes energy as well. Still more energy is needed to start breaking bonds in reactants. The graphs in Figure below show the changes in energy in endothermic and exothermic reactions. Both reactions need the same amount of activation energy in order to begin. Q: What is required to break bonds in reactants? Choices: - food - gas - protein - energy A:
Answer: energy
*Question*
Answer the following question given this paragraph: Many transition metals and their compounds are used as catalysts. Given MnO 2, FeCl3, Pt, and Ni, which would you select for each purpose and why?. Q: Many transition metals and their compounds are used as what? Choices: - insulators - bases - sealants - catalysts A:
**Answer**
catalysts
(Q).
Answer the following question given this paragraph: 22.6 The Hall Effect We have seen effects of a magnetic field on free-moving charges. The magnetic field also affects charges moving in a conductor. One result is the Hall effect, which has important implications and applications. Figure 22.27 shows what happens to charges moving through a conductor in a magnetic field. The field is perpendicular to the electron drift velocity and to the width of the conductor. Note that conventional current is to the right in both parts of the figure. In part (a), electrons carry the current and move to the left. In part (b), positive charges carry the current and move to the right. Moving electrons feel a magnetic force toward one side of the conductor, leaving a net positive charge on the other side. This separation of charge creates a voltage , known as the Hall emf, across the conductor. The creation of a voltage across a current-carrying conductor by a magnetic field is known as the Hall effect, after Edwin Hall, the American physicist who discovered it in 1879. Q: The creation of a voltage across a current-carrying conductor by a magnetic field is known as what? Choices: - off effect - newton effect - show effect - hall effect A:
(A).
hall effect