FILL IN THE BLANK . The close relationship that exists when two or more species live together is called _ .

Which statement correctly describes a way that mutations increase the likelihood that a species will survive in a changing environment

Which of these is an example of land degradation? a. containers designed to store pollutants leak. b. fertilizers provide too many nutrients to crops. c. garbage is buried so the land can be reclaimed later. d. a drought kills all the plants in an area, leaving bare land

Several billion years ago which gas was the least prevailant in the atmosphere