article: You may know the saying: An apple a day keeps the doctor away. A recent study by the Chinese University of Hong Kong has discovered another saying: An apple a day keeps old age away.
  The study involved fruit flies(g), as they share many genes  with humans. Researchers gave one group of fruit flies normal food, and another group of fruit flies got the same food including apple.
  The results showed that flies that ate apple lived an average of 55 days longer than the flies that didn't eat apple. The study also found that apple-eating flies were more able to walk, climb and move about as they became old, the Journal of Agricultural and Food Chemistry reports.
  The researchers believe that the antioxidants  found in apples are good for health.
  In another experiment, researchers studied the diets of thousands of women. They found that those women who often ate apples were 20 percent less likely to have heart disease.
  Scientists have recently discovered the apple's genetic code . This allows scientists to make new kinds of fruit that are healthier. Researchers are already using this information to grow apples with added antioxidants. Antioxidants help to keep eyes and joints  healthy and protect against heart attacks and cancer.
  Apples that help people lose weight may be in supermarkets in just four or five years. They are said to be "extra healthy" apples that can stop people from overeating.
question: By studying the diets of many women, researchers   _   .
options: proved apples were good for people's health. found they are healthier than men helped them to lose weight successfully discovered the genetic code of the apple