Final answer:
The expression 5x⁷ is a monomial because it fits the definition by being a single term that is a product of a constant and a variable raised to a whole number exponent.
Step-by-step explanation:
The expression 5x⁷ is indeed a monomial. A monomial is a mathematical expression that consists of a single term, which can be a constant, a variable raised to a whole number exponent, or a product of a constant and a variable raised to a whole number exponent. In this case, 5x⁷ consists of a constant (5) multiplied by a variable (x) raised to a whole number exponent (7), which fits the definition of a monomial. Therefore, the correct answer is option (a) Yes, it is a monomial.