The things it does or the appearance of the male reptile and the female reptile. they may have different sizes or thinner or thicker stripes and so on.
Human Beings The difference is that the boy has a penis and an Adams Apple. Girls have no Adams apple and when going through puberty girls get a period for which they have to use tampons or pads.
Males have a Y chromosome and an X chromosome while females have two X chromosome. At the very least this is true for mammals. Also males produce sperm that is meant to fertilize the eggs the females...
Yes- female gorillas have much larger breasts than the males, And they are usually the ones that look after the babies, whereas males have much flatter, broader chests (and usually have a penis as...