Describe the distinguishing organisms and major biological events associated with the following geological time
units.
A. Precambrian time
B. Paleozoic era
C. Mesozoic era
D. Cenozoic era What will be an ideal response?
Concepts to Consider: Precambrian--bacteria, protists, fungi and simple multicellular
animals. Paleozoic era--all major groups of plants (except angiosperms) and all animal phyla
appeared; also associated with the largest extinction event. Mesozoic--diversification of
reptiles, including dinosaurs, and the appearance of flowering plants, insects, birds, and early
mammals; a major extinction event, probably due to a meteor impact, resulted in a massive
extinction at the end of this era. Cenozoic era--continued diversification of flowering plants,
birds, insects, and mammals.
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Subway air and water distribution systems harbor dangerous levels of pathogenic microorganisms
Indicate whether the statement is true or false.
Deep ocean organisms expend little energy to stay afloat because
a. they have air bladders. b. they have a high oil content. c. of their small size. d. they are the same density as the surrounding environment. e. their metabolism is high.
Hematocrit approximately makes up what percent of the total blood volume?
a. 10 percent b. 25 percent c. 45 percent d. 50 percent e. 70 percent
The sum total of all chemical reactions that occur within an organism. Also, a specific set of chemical reactions occuring at the cellular level.