Section: Paragraph Comprehension

105) Regular weight lifting has been shown to improve muscle mass in people of all ages. Even 80 year old subjects in weight lifting studies show signs of benefits by supplementing their muscle mass.

It can be inferred from the passage that

young people do not benefit from weight lifting.
weight lifting even once a week will produce benefits for all ages.
older people show the most improvements in muscle mass in weight lifting studies.
any able body person can begin weight lifting at any age and see benefits.