What percentage of hits are of animal origin?

• A. 5%
• B. 12%
• C. 25%
• D. 6%

Answer: (D)

Animal-origin hits are a minority in natural-product screening. In most discovery datasets, the majority of hits come from plants and microbes, while animal sources contribute only a small fraction because of limited biodiversity, practical and ethical constraints, and the relative abundance and accessibility of non-animal materials. In the data represented by this question, the animal-derived portion is about a mid-single-digit percentage, around 6%. That makes 6% the best estimate, since it reflects a small but non-negligible contribution from animal sources. The other options would either overstate or understate this share, not aligning with how rarely animal-derived hits appear compared with other origins.