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

Input: Consider Input: Passage: Figure 5.3 This phospholipid molecule is composed of a hydrophilic head and two hydrophobic tails. The hydrophilic head group consists of a phosphate-containing group attached to a glycerol molecule. The hydrophobic tails, each containing either a saturated or an unsaturated fatty acid, are long hydrocarbon chains. Answer: hydrophillic head , and hydrophobic tails

Output: What two things are a phospholipid molecules composed of?

Input: Consider Input: Passage: Kevin Walsh. Cows are able to digest grass with the help of the bacteria methanogens in their gut . CC BY 2.0. Answer: bacteria

Output: A type of what in a cow's gut enables the animal to digest grass?

Input: Consider Input: Passage: The role a species plays in the ecosystem is called its niche. Answer: the ecosystem
Output: Niche refers to the role a species plays in what?