Given a scientific question, generate a correct answer to it.

Input: Consider Input: What process allows plants to convert light energy into sugars and energy for food?

Output: photosynthesis

Input: Consider Input: Bacteria, viruses, fungi, and protozoa are examples of what, the term for a disease-causing microorganism?

Output: pathogen

Input: Consider Input: What is a primary source of the hormone melatonin?
Output: pineal gland