Matter can undergo chemical reactions and nuclear reactions. Which property is conserved in nuclear reactions?

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?

The substances that are necessary for producing of certain hormones and that store and transport vitamins

Why does lightning travel from clouds to the ground?