17. Which of the following best states the central idea of the passage?
(A) The War of Independence produced among many Black Americans a heightened consciousness of the inequities in Ameri- can society.
(B) The War of Independence strengthened the bonds of slavery of many Black Ameri- cans while intensifying their desire to be free.
(C) The War of Independence exposed to many Americans the contradiction of slavery in a country seeking its freedom and resulted in efforts to resolve that contradiction.
(D) The War of Independence provoked strong criticisms by many Americans of the institution of slavery, but produced little substantive action against it.
(E) The War of Independence renewed the efforts of many American groups toward achieving Black emancipation.
18. The passage contains information that would support which of the following statements about the colonies before the War of Independence?
(A) They contained organized antislavery societies.
(B) They allowed individuals to own slaves.
(C) They prohibited religious groups from political action.
(D) They were inconsistent in their legal definitions of slave status.
(E) They encouraged abolitionist societies to expand their influence.
19. According to the passage, the War of Indepen- dence was embarrassing to some Americans for which of the following reasons?
I. It involved a struggle for many of the same liberties that Americans were denying to others.
II. It involved a struggle for independence from the very nation that had founded the colonies.
III. It involved a struggle based on inconsis- tencies in the participants' conceptions of freedom.
(A) I only (B) II only (C) I and II only
(D) I and III only (E) I, II, and III
20. Which of the following statements regarding American society in the years immediately following the War of Independence is best supported by the passage?
(A)The unexpected successes of the anti- slavery societies led to their gradual demise in the Eastern states.
(B) Some of the newly independent American states had begun to make progress toward abolishing slavery.
(C) Americans like Abigail Adams became disillusioned with the slow progress of emancipation and gradually abandoned the cause.
(D) Emancipated slaves gradually were accepted in the Eastern states as equal members of American society.
(E) The abolition of slavery in many Eastern states was the result of close cooperation between religious groups and free Blacks.
The evolution of sex ratios has produced, in most plants and animals with separate sexes, approxi- mately equal numbers of males and females. Why should this be so? Two main kinds of answers have been offered. One is couched in terms of advantage to population. It is argued that the sex ratio will evolve so as to maximize the number of meetings between individuals of the opposite sex. This is essentially a "group selection" argument. The other, and in my view correct, type of answer was first put forward by Fisher in 1930. This "genetic" argument starts from the assumption that genes can influence the relative numbers of male and female offspring produced by an individual carrying the genes. That sex ratio will be favored which maximizes the number of descen- dants an individual will have and hence the number of gene copies transmitted. Suppose that the popula- tion consisted mostly of females: then an individual who produced sons only would have more grand- children. In contrast, if the population consisted mostly of males, it would pay to have daughters. If, however, the population consisted of equal numbers of males and females, sons and daughters would be equally valuable. Thus a one-to-one sex ratio is the only stable ratio; it is an "evolutionarily stable strategy." Although Fisher wrote before the mathe- matical theory of games had been developed, his theory incorporates the essential feature of a game- that the best strategy to adopt depends on what others are doing.
Since Fisher's time, it has been realized that genes can sometimes influence the chromosome or gamete in which they find themselves so that the gamete will be more likely t
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