请高手讲讲下面几道题目:
Q34:
During the month of May, crabs arrive on Delaware’s beaches to lay eggs. Certain shorebirds depend on these eggs for food during their annual spring migration to their northern breeding grounds. Delaware’s crab population has declined recently. This decline, however, poses no serious threat to the migrating shorebird populations: by remaining longer in Delaware, the birds will be able to eat enough crab eggs to allow them to complete their migration.
Which of the following, if true, most seriously weakens the argument?
- No other food available to the birds on Delaware’s beaches is as nutritious and accessible as are crab eggs.
- The decline in the number of crabs on Delaware’s beaches is due to the harvesting of crabs by humans.
- There are more crabs on Delaware’s beaches than in any other area that the migrating birds pass through.
- The crabs do not conceal their eggs.
E:The earlier in the season the shorebirds complete their migration, the more likely they are to breed successfully.
(ans:e ,at first I chose A,but later I found e is resonable,but I am not sure about A...)
Q19:
A diet high in saturated fats increases a person’s risk of developing heart disease. Regular consumption of red wine reduces that risk.  er-capita consumption of saturated fats is currently about the same in France as in the United States, but there is less heart disease there than in the United States because consumption of red wine is higher in France. The difference in regular red-wine consumption has been narrowing, but no similar convergence in heart-disease rates has occurred.
Which of the following, if true, most helps to account for the lack of convergence noted above?
- Consumption of saturated fats is related more strongly to the growth of fatty deposits on artery walls, which reduce blood flow to the heart, than it is to heart disease directly.
- Over the past 30 years, per-capita consumption of saturated fats has remained essentially unchanged in the United States but has increased somewhat in France.
- Reports of the health benefits of red wine have led many people in the United States to drink red wine regularl
- Cigarette smoking, which can also contribute to heart disease, is only slightly more common in France than in the United States.
- Regular consumption of red wine is declining dramatically among young adults in France, and heart disease typically does not manifest itself until middle age.
(ans:e, I dont anderstand it clearly)
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