CHAPTER 1: Concepts and Methods in Biology

About 4.6 billion years ago remnants of exploding stars began to condense into planets around the sun. 2. The earth was initially very hot, but cooled to form an outer mantle and partially-molten core. ... Many parasitic types form resistant cysts. 4. A few protozoans are famous for the diseases they cause in humans. ... but only about 100 ... ................
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