Explanation should include that rate (used for Navy) or rank (used for all other branches)

is a designation to determine level of authority
is to be rendered appropriate respect/courtesy and distinction
is displayed on the uniform and elsewhere.

Explanation should include that grade

is a term used for determining pay categories across all branches of the uniformed services of the United States to govern wages, benefits, and entitlements, based on the corresponding military rank
is indicated by the numerals (1–9, with 9 being the highest rate of pay) after the rank/rate of E (enlisted personnel), W (warrant officers), or O (commissioned officers).

Example: The lowest enlisted personnel is E-1, enlisted at the lowest or base rate of pay, and would be labeled as such across every U.S. military branch.

Process/Skill Questions:

What is the role of the noncommissioned officer (NCO)?
What are the five purposes of NCOs?
Who was Major General Lejeune and what were his precepts defining the relationship that exists between Marine officers and the enlisted?
What is the role of officers for the Marine Corps and the MCJROTC?
Why does the military have ranks/rates?
How does rank relate to responsibility?
What does grade mean in the military?
What is the difference between grade and rank/rate?
What is the rank associated with a pay grade of E-4?