Consider the following statements: P: Combinatorics is always invoked in the modeling of physical phenomena. Q: Modeling some physical phenomena involves assigning probabilities to combinatorial possibilities in order to compute average values of physical quantities. Based on the passage above, what can be inferred about statements P and Q?

To determine the truth values of statements P and Q based on the passage:

1. Statement P: "Combinatorics is *always* invoked in the modeling of physical phenomena."

   • The passage states: *"This kind of counting is sometimes used in the modeling of several physical phenomena."*

   • Since it is only *sometimes* used rather than universally or always used, statement P is False.

2. Statement Q: "Modeling some physical phenomena involves assigning probabilities to combinatorial possibilities in order to compute average values of physical quantities."

   • The passage states: *"Often, in such models, the different combinatorial possibilities are assigned probability values. Assigning probabilities enables the computation of the average values of physical quantities."*

   • This directly confirms that for some physical phenomena, probabilities are assigned to combinatorial outcomes to calculate average values. Hence, statement Q is True.

Therefore, P is False and Q is True, which corresponds to option (B).