Chromosomes are made of proteins and DNA. They are present in the nuclei of the cells.In sexually reproducing organisms, the gametes undergo meiosis and hence, each gamete contains only half set of chromosomes. When two gametes fuse, the zygote formed contains the full set of chromosomes.Hence, the formation of gametes by meiosis helps to maintain the number of chromosomes in PROGENCY. 
Chromosomes are made up of proteins which are found in nucleus of the cell . as the sex cells are haploid so they both carry 23 chromosomes with which both the gametes  fuse they form 46 chromosomes hence  no. of chromosomes in the progency is maintaine