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

[EX Q]: On a global scale, plants and other photosynthetic organisms have generated all of the oxygen in the air.
[EX A]: On a global scale, plants and other photosynthetic organisms have generated all of what element in the air?

[EX Q]: A pregnant woman should avoid toxic substances while pregnant.
[EX A]: What should a pregnant woman avoid while pregnant?

[EX Q]: Pollen do bees carry from one plant to another to facilitate plant growth and development.
[EX A]:
What do bees carry from one plant to another to facilitate plant growth and development?