Final answer:
The two modes of fire for the M16A2E3 are auto and semi-automatic.
Step-by-step explanation:
The two modes of fire for the M16A2E3 are auto and semi-automatic.
In the auto mode, the rifle fires continuously as long as the trigger is held down. This mode is useful in situations where a high rate of fire is needed, such as suppressing enemy fire.
In the semi-automatic mode, the rifle fires one round with each pull of the trigger. This mode allows for greater accuracy and conserves ammunition.