Because LBJ, under the Tolkien Resolution, was given basically infinite power to protect U.S interests in Vietnam. Thus, President Johnson continued to "escalate", or build up American forces, weapons, and intervention in Vietnam. Now, somewhat opposite of this would be "Vietnamization" under Nixon, which was the gradual withdrawal of American troops but a continuation of supplies in order to aid South Vietnam from the Vietcong.
B because when one started helping the they all started helping
Black powder because without it, we'd have no guns/canons to use as weapons.
