TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: Phospholipids are vesicles made of.

SOLUTION: What are vesicles made of?

PROBLEM: A(n) an ionic bond forms when the metal sodium gives up an electron to the nonmetal chlorine.

SOLUTION: What forms when the metal sodium gives up an electron to the nonmetal chlorine?

PROBLEM: The end of a pine tree branch bears the male cones that produce pollen.

SOLUTION:
The end of a pine tree branch bears the male cones that produce what?