Answer: a constant
Step-by-step explanation:
A constant is a numerical expression like 2, 0,78 etc .
A variable is a alphabetical expression that vary like a,b,c,d,x,y,z.
An expression can consists of both numerical and alphabets and also any arithmetic expression like x, 2abc, 6a+2c etc
A term consist of either numbers and variables multiplied together or only numbers or variable like 2xy, x, 2ab etc.
X is all (a term, a variable , an expression) except a constant because a constant is a numerical expression.
