What type of biscuits did the soldiers eat in world war 1?

During World War I, soldiers on both sides were often issued hardtack or ship's biscuit as part of their rations. Hardtack is a simple cracker made from flour, water, and salt, and may have sometimes been called a biscuit. They can last for long periods without spoiling making them suitable for wartime conditions. In some circumstances there would be no time to have meals so soldiers would carry some with them while marching or moving into positions.