Chapter 1: Principles of LifeMultiple Choice1. If we picture the history of Earth as a 30-day month, modern humans arosea. at the beginning of week 4.b. on day 27.c. in the last 5 minutes of day 30.d. on day 15.e. in the early morning of day 30.Answer: c2. Yeasts can be used to study human cancer because yeasts and humans3. All living organisms can be assigned to three separate4. The basic structural and physiological unit of all living organisms is the5. Scientists estimate that for more than _______ years after cells originated, all organisms consisted of one cell.a. 2500b. 250,000c. 2 milliond. 2 billione. 2 trillionAnswer: d6. The initial accumulation of oxygen in the atmosphere was the result of photosynthesis from an organism most like modern7. A final prerequisite for the survival of life on land was the accumulation of a protective layer of8. The chemical formula for oxygen is9. Ozone is important to life on Earth because ita. is toxic to all forms of life.b. can be used in place of oxygen.c. blocks much ultraviolet radiation.d. provides energy to some basic forms of life.e. acts as a disinfectant.Answer: c10. A cell11. You propose a set of experiments to test whether present-day chloroplasts originated from a single or multiple endosymbiotic events. Which set of experiments below would provide the most detailed test of the hypothesis?
chloroplasts that look the same at the 4 nm resolution of electron microscopy
- Winter '17
- Bacteria, d., c.