Q: Q: The theory of evolution by what (and other processes) explains both the diversity of organisms and how populations of organisms change over time? Read this paragraph and choose the correct option from the provided answers: Biology has only a few over arching theories. One of these, the Cell Theory of Life, explains the historic continuity of organisms, while the Theory of Evolution by Natural Selection (and other processes), explains both the diversity of organisms and how populations of organisms change over time. Finally, the Physicochemical Theory of Life explains how it is that organisms can display their remarkable properties without violating the laws that govern all physical and chemical systems.40 What is life, exactly? Clearly, if we are going to talk about biology, and organisms and cells and such, we have to define exactly what we mean by life. This raises a problem peculiar to biology as a science. We cannot define life generically because we know of only one type of life. We do not know whether this type of life is the only type of life possible or whether radically different forms of life exist elsewhere in the universe or even on Earth, in as yet to be recognized forms. While you might think that we know of many different types of life, from mushrooms to whales, from humans to the bacterial communities growing on the surfaces of our teeth (that is what dental plaque is, after all), we will discover that the closer we look the more these different "types of life" are in fact all versions of a common underlying motif, they represent versions of a single type of life. Based on their common chemistry, molecular composition, cellular structure, and the way that they encode, read, and use hereditary information in the form of molecules of deoxyribonucleic acid (DNA), all topics we will consider in depth later on, there is no reasonable doubt that all organisms are related, they are descended from a common ancestor. We cannot currently answer the question of whether the origin of life is a simple, likely, and predictable event given the conditions that existed on the Earth when life first arose, or whether it is an extremely rare and unlikely event. In the absence of empirical data, one can question whether scientists... Choices: - natural evolution - characteristic selection - genocide - natural selection A:
A: natural selection

Q: Q: Acids are associated with a low number on which scale? Read this paragraph and choose the correct option from the provided answers: As indicated in http://catalog. flatworldknowledge. com/bookhub/reader/2547 - gob-ch10_s04, weak acids are relatively common, even in the foods we eat. But we occasionally come across a strong acid or base, such as stomach acid, that has a strongly acidic pH of 12. By definition, strong acids and bases can produce a relatively large amount of hydrogen or hydroxide ions and, as a consequence, have a marked chemical activity. In addition, very small amounts of strong acids and bases can change the pH of a solution very quickly. If 1 mL of stomach acid [which we will approximate as 0.05 M HCl(aq)] is added to the bloodstream, and if no correcting mechanism is present, the pH of the blood would go from about 7.4 to about 4.9a pH that is not conducive to continued living. Fortunately, the body has a mechanism for minimizing such dramatic pH changes. The mechanism involves a buffer, a solution that resists dramatic changes in pH. Buffers do so by being composed of certain pairs of solutes: either a weak acid plus a salt derived from that weak acid or a weak base plus a salt of that weak base. For example, a buffer can be composed of dissolved acetic acid (HC2H3O2, a weak acid) and sodium acetate (NaC2H3O2, a salt derived from that acid). Another example of a buffer is a solution containing ammonia (NH3, a weak base) and ammonium chloride (NH4Cl, a salt derived from that base). Let us use an acetic acidsodium acetate buffer to demonstrate how buffers work. If a strong basea source of OH(aq) ionsis added to the buffer solution, those hydroxide ions will react with the acetic acid in an acid-base reaction: HC2H3O2(aq) + OH(aq) H2O() + C2H3O2(aq) Rather than changing the pH dramatically by making the solution basic, the added hydroxide ions react to make water, and the pH does not change much. Choices: - metric - acidic - ionic - ph A:
A: ph

Q: Q: What substances are involved in most of the chemical reactions that take place in organisms, including digestion? Read this paragraph and choose the correct option from the provided answers: Enzymes are involved in most of the chemical reactions that take place in organisms. About 4,000 such reactions are known to be catalyzed by enzymes, but the number may be even higher. In animals, an important function of enzymes is to help digest food. Digestive enzymes speed up reactions that break down large molecules of carbohydrates, proteins, and fats into smaller molecules the body can use. Without digestive enzymes, animals would not be able to break down food molecules quickly enough to provide the energy and nutrients they need to survive. Choices: - proteins - hormones - vitamins - enzymes A:
A: enzymes

Q: Q: What's it called when gases turn back into liquids? Read this paragraph and choose the correct option from the provided answers: As water cools in the clouds, condensation occurs. Condensation is when gases turn back into liquids. Choices: - dehydration - diffusion - evaporation - condensation A:
A: condensation