81.5%, 0.815, 33/40 least to greatest

Step-by-step explanation:

Part A

The degree if a polynomial is the highest power to which its variable is raised. A fifth degree polynomial is one in which the highest power to which its variable is raised is 5.

Example of such polynomial is

3x^5 + 4x^4 + 6x^3 + 4x^2 - 30

It is in standard form because the powers to to which the variable is raised is decreasing orderly.

Part B

The closure property of polynomials when subtracting leads to a possible change in the coefficients of the polynomial only. Example is

(5x² + 3x + 2) - (3x² + x + 1) = 5x² - 3x² + 3x - x + 2 -1 = 2x² + 2x + 1