7.Why is axiom 5, in the list of Euclid’s axioms, considered a 'universal truth'?

(Note that, the question is not about the fifth postulate.)

(Note that, the question is not about the fifth postulate.)

According to axiom 5, we have 'The whole is greater than a part', which is a universal truth.

Let a line segment PQ = 8cm. Consider a point R in its interior, such that PR = 5cm.

Clearly, PR is a
part of the line segment PQ and R lies in its interior.

Hence, PR is smaller than PQ.

Hence, the whole is greater than its part is proved.