Yes, a boa is considered a reptile. Specifically, boa constrictors belong to the class Reptilia and the family Boidae, which includes large, nonvenomous snakes.
A boa constrictor can hurt a human by constriction if it feels threatened or provoked, as they kill prey by wrapping around and squeezing. However, attacks on humans are very rare and boas are generally not aggressive unless mishandled or feeling endangered.
Yes, snakes are reptiles. They belong to the order Squamata, which includes lizards and snakes, with boas being a genus within this order.
Boa constrictors are usually not very aggressive. They tend to rely on camouflage and constriction for hunting rather than attacking indiscriminately, and may display defensive behaviour if threatened but are not naturally hostile towards humans.