Given scientific fact as input, generate the question from this fact such that it can be answered from the input.

Axillary buds in the axils of leaves and stems give rise to branches.
What in the axils of leaves and stems give rise to branches?

Plant nutrition is the study of the chemical elements necessary for plant growth.
What is the study of the chemical elements necessary for plant growth called?

Centripetal force is the force that causes centripetal acceleration.
What is the force that causes centripetal acceleration?