A、The cause of A. M. D. B、The methods to reduce the risk of A. M. D. C、The link between smoking and A. M. D. D、The ways to stop

Two studies are suggesting ways to reduce the risk of A. M. D, that is age-related macular degeneration.[33]A. M. D. is the main cause of blindness among older adults. The disease makes seeing less and less clear and in time leads to blindness.
    One study found that cigarette smokers were almost two times as likely to develop A. M. D. as people who did not smoke. The study involved men with twin brothers, almost 700 individuals. The average age was about 75.[34]The men were asked questions about their diet and history of cigarette smoking, alcohol use and physical activity. Some of the men already had A. M. D.
The study found that the men who ate more fish, even those who smoked cigarettes, were less likely to develop A. M. D. Those who ate more than two meals a week containing fish were the least likely to develop the disease.
    A second study produced similar results. It found that people who ate at least one meal containing fish each week were 40 percent less likely to develop A. M. D.
    Researchers studied information on almost 3, 000 people. Each person was 49 years of age or older. They were asked about their diet and medical history, and then tested for the disease after five years.
    The results of both studies have not yet been confirmed. But they do show a possible link between eating fish and prevention of A. M. D.
    Researchers say the best fish to eat are those high in omega-three fatty acids. Some people take fish oil supplements that also have them.
32.What are the two studies aimed to find?
33.What does A. M. D. refer to?
34.Which of the following statements is true according to the passage?
35.What can we learn from the two studies?