Which of the following best describes a polynomial expression?

A polynomial expression is defined as an algebraic expression that includes variables, which are raised to non-negative integer powers, and combined using addition, subtraction, and multiplication. This means that in a polynomial, the exponents on the variables must be whole numbers (i.e., 0, 1, 2, etc.), and cannot be negative or fractional.

For example, the expression (3x^2 + 2x + 5) qualifies as a polynomial since the variable (x) has non-negative integer powers (2 and 1), and is also combined with coefficients (3, 2, and 5).

This definition is crucial because it ensures that polynomial expressions maintain specific properties such as closure under addition and multiplication. These properties are fundamental in algebra and calculus, particularly when solving polynomial equations or working with polynomial functions.

The other options do not capture the full definition of polynomial expressions. For instance, an expression with variables and negative powers (the first option) violates the non-negative integer power condition, while an expression consisting solely of numerical constants (the second option) lacks variables entirely, making it a constant rather than a polynomial. The fourth option, referring to a graph-related term, does not pertain to