TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: Some compounds form rigid frameworks called crystals.

SOLUTION: Some compounds form rigid frameworks called what?

PROBLEM: Altricial organisms are helpless at birth and require lots of help from their parents.

SOLUTION: What type of organisms are helpless at birth and require lots of help from their parents?

PROBLEM: Electrons in successive atoms on the periodic table tend to fill low-energy orbitals first.

SOLUTION:
What type of orbitals do electrons in successive atoms on the periodic table tend to fill first?