<span>The angiosperms became more common during the cretaceous period. The Cretaceous period occurred almost 144 million years ago and it followed the Jurassic period. </span>
Mutations. Definition. A Mutationoccurs when a DNA gene is damaged or changed in such a way as to alter the genetic message carried by that gene. A Mutagen is an agent of substance that can bring about a permanent alteration to the physical composition of a DNA gene such that the genetic message is changed
Selective logging—the practice of removing one or two trees and leaving the rest intact—is often considered a sustainable alternative to clear-cutting, in which a large swath of forest is cut down, leaving little behind except wood debris and a denuded landscape