The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data? (A) Forelimb evolution was adaptive in people and bats, but not in whales. (B) Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy. (C ) Genes mutate faster in bats than in humans or whales. (D) Whales are not properly classified as mammals.

Review the relationship between genotype and phenotype . Suppose that in a particular pea population, flowers with the white phenotype are favored by natural selection. Predict what would happen over time to the frequency of the p allele in the population, and explain your reasoning.

Describe an experiment to test your prediction.

Predict what would happen if, after 22 months, guppies from the transplanted population were returned to the source pool.

What conclusion do you draw from the data presented above?

Within six months of effectively using methicillin to treat $S.aureus$ infections in a community, all new $S.aureus$ infections were caused by a resistant strain (MRSA). How can this best be explained? (A) A patient must have become infected with MRSA from another community. (B) In response to the drug, S. aureus began making drug-resistant versions of the protein targeted by the drug. (C ) Some drug-resistant bacteria were present at the start of treatment, and natural selection increased their frequency. (D) $S.aureus$ evolved to resist vaccines.

$\text{\blue{WHAT IF?}}$ Fossils show that dinosaurs originated 200–250 million years ago. Would you expect the geographic distribution of early dinosaur fossils to be broad (on many continents) or narrow (on one or a few continents only)? Explain.

Predict which of the following compounds are ionic and which are covalent, based on the location of their constituent atoms in the periodic table: (a) $\mathrm{Cl}_2 \mathrm{CO}$ (b) $\mathrm{MnO}$ (c) $\mathrm{NCl}_3$ (d) $\mathrm{CoBr}_2$ (e) $\mathrm{K}_2 \mathrm{~S}$ (f) $\mathrm{CO}$ (g) $\mathrm{CaF}_2$ (h) $\mathrm{HI}$ (i) $\mathrm{CaO}$ (j) $\mathrm{IBr}$ (k) $\mathrm{CO}_2$

Lovato Motors Inc. has cash flows from operating activities of $720,000. Cash flows used for investments in property, plant, and equipment totaled$440,000, of which 85% of this investment was used to replace existing capacity. Determine the free cash flow for Lovato Motors Inc.

How does evolution account for (a) the similar mammalian forelimbs with different functions shown in Figure 22.15 and (b) the similar forms of the two distantly related mammals shown in Figure 22.18?

$\text{\blue{MAKE CONNECTIONS}}$ Scientific hypotheses must be testable (see Concept $1.3$). Applying this criterion, are Cuvier’s explanation of the fossil record and Lamarck’s hypothesis of evolution scientific? Explain your answer in each case.

Review the relationship between genotype and phenotype (see Figures 14.5 and 14.6). Suppose that in a particular pea population, flowers with the white phenotype are favored by natural selection. Predict what would happen over time to the frequency of the whiteflower allele (the p allele) in the population.

Explain how the types of data the researchers chose to collect enabled them to test their prediction.

Gallium (Ga) consists of two naturally occurring isotopes with masses of 68.926 and 70.925 amu. How many protons and neutrons are in the nucleus of each isotope? Write the complete atomic symbol for each, showing the atomic number and mass number.