Concept:Real numbers include both rational and irrational numbers. These two sets are disjoint, meaning a number cannot be both rational and irrational.
Explanation:Option A: Every integer is a real number — True, because integers belong to the set of real numbers.
Option B: Every natural number is an integer — True, natural numbers are a subset of integers.
Option C: Every irrational number is rational — False, irrational numbers cannot be expressed as a ratio of integers, so they are not rational.
Option D: Rational and irrational numbers are real numbers — True, both form the complete set of real numbers.
Answer:The false statement is option C.