Scientists estimate that the earth formed some 4.6 billion years ago with the first forms of life appearing around 3.5 billion years ago. these first forms of life were simple prokaryotes. later, the first photosynethic organisms resulted in more in the atmosphere. this allowed for more higher level organisms to appear on earth. a) carbon b) nitrogen c) oxygen d) sulfur

Wich organism obtains its energy from dead or decaying matter

Sarah and john are having a discussion on genetic diversity. sarah believes that it happen over a long period of time. john it happens immediately. who is correct? a. sarah is correct because genetic diversity occurs over a long period of time. b. john is correct because genetic diversity occurs immediately. c. both are correct because genetic variation can occur or long period of time. d. neither are correct because genetic diversity occurs over any period of time

If a cell is placed into a hypertonic environment, what will happen to it ? a)it will shrink or shrivel b)nothing c)it will burst d) it will expand or enlarge