TASK DEFINITION: Given scientific fact as input, generate the question from this fact such that it can be answered from the input.
PROBLEM: Three many families are known quarks divided into.

SOLUTION: How many families are known quarks divided into?

PROBLEM: Do particles collide more in two reactants fluid they are both in fluid forms or solid forms.

SOLUTION: Do particles collide more in two reactants when they are both in fluid forms or solid forms?

PROBLEM: 2050 is the predicted year that as many as half of all remaining species could go extinct.

SOLUTION:
What is the predicted year that as many as half of all remaining species could go extinct?