Why was waging war in vietnam difficult for u. s. soldiers?
north vietnamese soldiers were highly trained and well-equipped.
the vietnamese terrain and climate were harsh and difficult.
u. s. soldiers were poorly equipped and lacked adequate training.
most south vietnamese the viet cong and north vietnamese.

The right answer is The Vietnamese terrain and climate were harsh and difficult.

After a long resistance from the Vietnamese, the US government gave in to political and popular pressures and withdrew from the conflict. This measure allowed communist North Vietnam to invade and conquer South Vietnam, unifying the nation. With a smaller army and worse equipped, the Vietnamese, who had a great knowledge under their territory, avoided great confrontations making strategic escapes by their areas. In addition, they encouraged the morale of their soldiers with the constant deaths of American soldiers, mainly through jungle traps. Ordinary and improvised mines were scattered throughout the jungle, especially around fallen trees. The traditional mines were triggered when one stepped on one of them and removed his foot. The improvised ones, however, contained a rifle cartridge that, when pressed, was pressed against a pin that detonated and fired.

the answer to fill in the blank in this question would be the word resource, it is defined as the money, material or people (since human resource is a very valuable good) that a company or a person has at disposition (meaning they can use the resource as they see fit), to be able to complete a task or achieve a goal.