instruction:
Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
question:
The mesopause is at the top of the mesosphere.
answer:
What is at the top of the mesosphere?

question:
The double helix dna shape forms when the two nucleotide chains wrap around the same axis.
answer:
What distinctive dna shape forms when the two nucleotide chains wrap around the same axis?

question:
Roots grow in length and width from the primary and secondary meristem.
answer:
Roots grow in length and width from the primary and secondary what?