a. 2 > The 23rd pair, the sex chromosomes, differ between males and females (females have two copies of the X chromosome, while males have one X and one Y chromosome). In humans, the sex chromosomes comprise one pair of the total of 23 pairs of chromosomes. The other 22 pairs of chromosomes are called autosomes. <em>Chromosomes are thread-like molecules that carry hereditary information (they are made of protein and one molecule of DNA, which contains an organism's genetic instructions).</em>
Alright bud the best answer to this question would be that one of the first scientists of the Renaissance to advance taxonomy through first hand observations was Cordus
