Final answer:
The National Institutes of Health (NIH) is the agency that supports research on the biological and behavioral aspects of critical health problems in the nation, contributing significantly to public health and the economy.
Step-by-step explanation:
The agency that supports research on the biological and behavioral aspects of critical health problems that confront the nation is a) National Institutes of Health (NIH). The NIH is a part of the U.S. Department of Health and Human Services and serves as the nation's premier medical research agency.
Its role is in making important discoveries that touch everyday life by improving health outcomes and saving lives. As supported by federal grants, the impact of the NIH's research is profound, contributing significantly to the nation's GDP and employment rates.
This demonstrates the importance of governmental support in fostering public goods through medical research and development.