What does the antitrust laws prevent?

Question

Please answer as soon as possible thanks.

Answer 1

monopolies

Answer 2

okay do you know what else

Answer 3

http://en.wikipedia.org/wiki/United_States_antitrust_law

Answer 4

but she said I can not used wikipedia cause it is based on opinions

Answer 5

http://www.google.com/#q=+antitrust+laws+

Answer 6

thanks