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: Water affects the availability of oxygen important element in aquatic environments and in flooded soils.

SOLUTION: Water affects the availability of what important element in aquatic environments and in flooded soils?

PROBLEM: Pathogens is the term for disease-causing agents, such as bacteria and viruses.

SOLUTION:
What is the term for disease-causing agents, such as bacteria and viruses?