Fluid intelligence is the type of intelligence that has to do with short-term memory and the ability to think quickly, logically, and abstractly in order to solve new problems. It
_____（1）in young adulthood, levels out for a period of time, and then_____（2）starts to slowly decline as we age. But_____（3）aging is inevitable, scientists are finding that certain changes in brain function may not be.
One study found that muscle loss and the_____（4）of body fat around the abdomen are associated with a decline in fluid intelligence. This suggests the_____（5）that lifestyle factors might help prevent or_____（6）this type of decline.
The researchers looked at data that_____（7）measurements of lean muscle and abdominal fat from more than 4,000 middle-to-older-aged men and women and_____（8）that data to reported changes in fluid intelligence over a six-year period. They found that middle-aged people_____（9）higher measures of abdominal fat_____（10）worse on measures of fluid intelligence as the years_____（11）.
For women, the association may be_____（12）to changes in immunity that resulted from excess abdominal fat; in men, the immune system did not appear to be_____（13）It is hoped that future studies could_____（14）these differences and perhaps lead to different_____（15）for men and women.
_____（16）there are steps you can_____（17）to help reduce abdominal fat and maintain lean muscle mass as you age in order to protect both your physical and mental _____（18）. The two highly recommended lifestyle approaches are maintaining or increasing your_____（19）of aerobic exercise and following Mediterranean-style_____（20）that is high in fiber and eliminates highly processed foods.