On the medieval world-maps it was represented only the part of the world known as the 'old world', which is consisted of Europe, Asia and Africa. Before the big discoveries, people living in this continents had knowledge only of this part of the world, while South and North America, Australia and Antarctica where still unknown to them, thus they are missing in the world-maps of this period.
Answer:
A prime number is a whole number greater than one who's only factors are one and itself. The prime symbol is usually used to A) denote two distinct but similar objects or B) to denote the derivative. It could be described as a seperator.