Siphoning fluids with a pipe is a common practice, despite the risk of choking. The water level in a tall tank is fairly low. A pipe is inserted into the water in the tank. A person sucks on the other end of the pipe lifting water by 1.0 m above the level of water in the tank but doesn't succeed in making water flow through the siphon. i) Determine the least gauge pressure attained inside the person's lungs during this activity. ii) Why is the pressure negative?