The pump unit takes water from the source and provides the right pressure for delivery into the pipe system. The control head consists of valves to control the discharge and pressure in the entire system. Some control head units contain a filter and fertilizer or nutrient tank. These slowly add a measured dose of fertilizer into the water during irrigation. This is one of the major advantages of drip irrigation over other methods.(1) What is the function of the pump unit in a drip system ?(2) Explain one of the major advantages of drip irrigation.