Some liquid is collected from the xylem of plant stem whats is the substance that present in this collected liquids?

mineral ions present in the liquid collection such as Mg2+ which is to be carried to the leaf of the plant essentially for chlorosis

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.