Grade 11 biology help? (it's about water pressure)?

Hi, so we did this experiment in my grade 11 biology cl where we poked three small holes in a vertical row from the bottom to the top of a plastic water bottle. Then we filled the bottle with water and had to observe the differences in water streams from each hole. The water flowed the most steadily and farthest from the bottom hole and the water barely flowed from the middle and top holes. Now, I have to explain why this happened, and I have no idea. It has to do with pressure, but I can't find information on it. If anyone can explain to me why, that'd be great!