What two structures generate the cells responsible for immune responses? B lymphocytes and T lymphocytes
thymus and lymphocytes
bone marrow and lymphocytes
bone marrow and thymus

Can somebody explain to me how newton's 3rd law relates to momentum? ~ap physics 1

An uplifted block of rock between two normal faults

Apulley system is used to lift a 2,000 newton engine up a distance of 3 meters. the operator must apply a force of 250 newtons to the chain of the pulley system to lift the motor. to lift the engine 3 meters, the operator must pull a total of 30 meters of chain through the pulley system. what is the value of di?