How can you tell the different between male and female guppies?

Male guppies are much more colourful, and have larger tails than females. As well as this, underneath the fish near their tail is a small fin, in males this is spiky, and in females this is a triangle. Females often have a larger more rounded belly than males.

can any one tell me how long a guppies stay pregnant (you can type this in the question bar up above) "how long do guppies stay pregnant"

also can some one answer this.. (type this in the bar ) "after the female guppy gives birth does the gravid spot go away)"

please answer back I'm desperate