Which ends up with half the number of chromosomes?

Meosis

Explanation:

Meosis 1 ends with 2 diploid cells that end up dividing again into 4 haploid cells.  Thus, the end result of meosis is 4 haploid cells with 23 chromosomes each.

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.