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

[Q]: Simple carbohydrates can be classified in terms of chain length.
[A]: Which carbohydrates can be classified in terms of chain length?

[Q]: Metabolism produces waste energy in the form of heat, which helps warm-blooded (endotherm) animals conserve and maintain heat at a relatively constant body temperature.
[A]: Metabolism produces waste energy in the form of heat, which helps what type of animal conserve and maintain heat at a relatively constant body temperature?

[Q]: Leukocytes blood cells are white.
[A]:
What color are leukocytes blood cells?