diploid cells have 2 sets of chromosomes, or 46 chromosomes.
haploid cells (such as sex cells) have only 1 set of chromosomes, or 23 chromosomes.
Chiasma- the point where two homologous non-sister chromatids exchange genetic material during chromosomal crossover during meiosis.
Tetrad- A group of four cells, as of spores or pollen grains, formed from a parent cell by meiosis.