Which factors led to stalemate in the trenches? Check all that apply.

Attacks across open ground toward defended trenches caused heavy casualties, making advances difficult. Defensive weapons, such as machine guns and barbed wire, were more effective than the weapons and tactics used to attack, and trenches were built to protect their occupants. These factors favored holding positions rather than capturing them. New technologies did not generally help attackers overtake trenches, so choice B is not correct.

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