Let \( A = \{0, 1, 2, 3, \dots\} \) be the set of non-negative integers. Let \( F \) be the set of functions from \( A \) to itself. For any two functions, \( f_1, f_2 \in F \), we define
\[
(f_1 \circ f_2)(n) = f_1(n) + f_2(n)
\]
for every number \( n \in A \). Which of the following is/are CORRECT about the mathematical structure \( (F, \circ) \)?