Question

scientific evidence. because medicines and medical practice were not always well regulated, early doctors were free to prescribe treatments - such as gold - without proof that they actually worked. modern research, however, indicates that gold does have some well - founded medical uses. for instance, gold salts have been shown to palliate the symptoms of rheumatoid arthritis. when patients receive regular injections of gold, it begins to accumulate in their muscles; this reduces joint inflammation, relieving pain and preventing further damage. researchers are also actively investigating the ability of gold nanoparticles to target cancer cells, which could help doctors identify the disease and deliver medication more efficiently. such findings confirm that gold is, as people have believed for thousands of years, rich in medical potential. what is the meaning of efficacy as used in the passage? accessibility safety effectiveness efficiency

Explanation:

The passage discusses how early doctors prescribed treatments (like gold) without proof they worked. Modern research shows gold has medical uses (e.g., palliating rheumatoid arthritis symptoms). The context implies a focus on whether treatments work (effectiveness). "Efficacy" relates to a treatment's ability to produce a desired result (effectiveness), not accessibility (availability), safety (freedom from harm), or efficiency (doing things in the best way).

Answer:

effectiveness