Final answer:
Ability can be trained and improved upon through education and practice. While there are many factors that influence an individual's intelligence, such as environment and genetics, no single factor is determinative. Education can enhance human capital, although there might be limits to the benefits it provides.
Step-by-step explanation:
The question at hand is whether ability can be trained and improved upon. The answer is that ability can indeed be trained and enhanced through various methods such as education, practice, and exposure to different experiences. Abilities are not fixed and can be developed over time with effort and the right training. This concept ties in closely with the importance of education in human capital deepening, which suggests that as individuals become more educated and knowledgeable, their capabilities can continue to grow, although there may be diminishing returns at certain points.
Regarding the influence on an individual's intelligence level, multiple factors come into play, including but not limited to the environment, genetics, education, and individual experiences. No one factor alone can dictate a person's intelligence, but rather it is the interplay of these elements. The environment in which a person is raised can be a strong predictor, but it does not solely determine one's future intelligence.