Question

what is a joule?
a. a unit of energy
b. a form of nuclear energy
c. the movement of heat
d. a unit of temperature

Explanation:

The joule is a unit in the International System of Units (SI). It is specifically defined as the unit of energy. Nuclear energy is a type of energy (not a unit), the movement of heat is related to concepts like heat transfer (not a unit), and the unit of temperature is the kelvin (or degree Celsius, Fahrenheit etc. in non - SI).

Answer:

A. A unit of energy