#### Answer

The expression is a polynomial. The degree of the polynomial is $2$.

#### Work Step by Step

RECALL:
(1) A monomial in one variable is a product of a constant and variable whose exponent is a nonnegative integer.
(2) A polynomial can be a monomial or a sum of monomials.
(3) The degree of a polynomial in one variable is equal to the degree of the term with the highest degree.
The given expression has two terms.
The first term has a variable $x$ with an exponent of $2$.
This term's degree is 2.
The second term has no variable, so its degree is 0.
The term with the higher degree is the first, whose degree is 2.
Thus, the given expression is a polynomial whose degree is 2.