(Q).
Q: Evolution occurs because of changes in what over time? Read this paragraph and choose the correct option from the provided answers: We now know how variation in traits is inherited. Variation in traits is controlled by different alleles for genes. Alleles, in turn, are passed to gametes and then to offspring. Evolution occurs because of changes in alleles over time. How long a time? That depends on the time scale of evolution you consider. Choices: - mitochondria - genomes - atoms - alleles A:
(A).
alleles

(Q).
Q: The uranium series is a chain constituting one what, which encompass naturally occurring isotopes of the heaviest elements? Read this paragraph and choose the correct option from the provided answers: Radioactive Decay Series The naturally occurring radioactive isotopes of the heaviest elements fall into chains of successive disintegrations, or decays, and all the species in one chain constitute a radioactive family, or radioactive decay series. Three of these series include most of the naturally radioactive elements of the periodic table. They are the uranium series, the actinide series, and the thorium series. The neptunium series is a fourth series, which is no longer significant on the earth because of the short half-lives of the species involved. Each series is characterized by a parent (first member) that has a long half-life and a series of daughter nuclides that ultimately lead to a stable end-productthat is, a nuclide on the band of stability (Figure 21.9). In all three series, the end-product is a stable isotope of lead. The neptunium series, previously thought to terminate with bismuth-209, terminates with thallium-205. Choices: - nuclear decay family - gland decay family - fuel decay family - radioactive decay family A:
(A).
radioactive decay family

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Q: What elements tend to conduct well? Read this paragraph and choose the correct option from the provided answers: While many elements differ dramatically in their chemical and physical properties, some elements have similar properties. We can identify sets of elements that exhibit common behaviors. For example, many elements conduct heat and electricity well, whereas others are poor conductors. These properties can be used to sort the elements into three classes: metals (elements that conduct well), nonmetals (elements that conduct poorly), and metalloids (elements that have properties of both metals and nonmetals). The periodic table is a table of elements that places elements with similar properties close together (Figure 1.22). You will learn more about the periodic table as you continue your study of chemistry. Choices: - organics - gases - oils - metals A:
(A).
metals