Given a scientific passage and an answer, generate a question for the given answer.

Example Input: Passage: Improving crops by selecting for certain genetic traits. The desired traits promote productivity. Recently, genetically engineered crops have been introduced. Answer: promotes productivity
Example Output: What is the advantage of selecting for certain genetic traits for crops?

Example Input: Passage: The global pattern of precipitation is influenced by movements of air masses. For example, there is a global belt of dry air masses and low precipitation at about 30 N and 30 S latitude. Answer: air masses
Example Output: The global pattern of precipitation is influenced by movements of what?

Example Input: Passage: Lipids A lipid is one of a highly diverse group of compounds made up mostly of hydrocarbons. The few oxygen atoms they contain are often at the periphery of the molecule. Their nonpolar hydrocarbons make all lipids hydrophobic. In water, lipids do not form a true solution, but they may form an emulsion, which is the term for a mixture of solutions that do not mix well. Answer: hydrocarbons
Example Output:
A lipid is one of a highly diverse group of compounds made up mostly of what?