Difference between level and flow transmitters

What is the difference between level transmitter, flow transmitter and DP transmitter

The level transmitter detects the level of the solution in the tank, if the level goes low…it sends a signal to control the valve to open/close. Flow transmitter, with its sensors…detects the amount of flow passing through the vessel. Also, send the signal to the control valve either to open/close. DP transmitter.differentiate the pressure in the pipe. Remember it has 2 sides. HP and LP.