Final answer:
The United States accounts for approximately 50% of global pharmaceutical R&D spending, reflecting its significant contribution to medicine. Funding is mainly industry-driven, supported by tax incentives, with historical shifts from federal to private funding.
Step-by-step explanation:
The percentage of worldwide research and development spending on pharmaceuticals based in the United States is approximately 50% (option b). This is a reflection of the strong pharmaceutical industry in the U.S., which is a significant contributor to the field of medicine and drug development. The funding for this research is mainly provided by industry, with a smaller contribution from the federal government and an even smaller one from universities and colleges.
Historically, the federal government paid for a larger share, but over time, industry-funded R&D has increased in importance. Despite these changes, pharmaceutical companies continue to invest heavily in the search for new medicines, including natural compounds which have yielded about 35 percent of new drugs between 1981 and 2002. Tax policies also influence this arena by providing tax breaks for research and development, encouraging further investment from industry.