Answer:
Describe the features that characterized the earliest animals and when they appeared on earth
Explain the significance of the Cambrian period for animal evolution and the changes in animal diversity that took place during that time
Describe some of the unresolved questions surrounding the Cambrian explosion
Discuss the implications of mass animal extinctions that have occurred in evolutionary history
Germ theory states that certain diseases are caused by the invasion of the body by microorganisms, organisms to small to be seen except through a microscope. The cell theory states that living things are composed of one or more cells, that the cell is the basic unit o life, and that cells arise from preexisting cells. The theories are similar because germ theory states that disease is caused by living organisms.
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Because the world is constantly evolving and changing, so nature has to keep up with that constant change with natural selection.
