Final answer:
There are no exclusions on the variable a for the given fraction.
Step-by-step explanation:
The exclusions placed on the variable a for the fraction a²m + 4m/a² + 4 can be found by identifying the values of a for which the denominator becomes zero. In this case, we need to solve the equation a² + 4 = 0 for a.
By subtracting 4 from both sides of the equation, we get a² = -4. Since the square of any real number cannot be negative, there are no real solutions for a that satisfy this equation. Therefore, there are no exclusions on the variable a for the given fraction.