Answer:
x^2, 4x^2, and 16x^2 are examples of like terms
Explanation:
In the expression 
 are examples of ____
 are examples of ____
Given expression is 

All the terms have same variable with same exponent.
Same exponent with same variables are called like terms.
In the given expression, all terms have same variable x^2
So x^2, 4x^2, and 16x^2 are examples of like terms