Consider the 4.6-billion-year history of the Earth. Geological and fossil evidence indicates that during the greatest fraction of its history, the Earth
a. was too hot to have either a solid surface or any form of life.
b. had organic molecules in liquid water, but no living forms.
c. had unicellular organisms, but not multicellular.
d. had both multicellular and unicellular organisms, but no terrestrial (land) forms.
e. had both terrestrial, freshwater, and marine organisms, both unicellular and multicellular.
C; The Earth was formed about 4.5 billion years ago. Prokaryotic life existed on Earth from about 3.8 billion years ago, thus the period before life first appeared was about 700 million years total (choices a and b). Multicellular forms appear about 900 years ago, making the period of only unicellular prokaryotes and eukaryotes to be about 2.9 billion years (correct choice c). Terrestrial forms appeared about 400 million years ago, making the period of multicellular and unicellular nonterrestrial forms about 500 million years (choice d).
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a. B cells, IgG b. T cells, IgA c. B cells, IgA d. T cells, IgE e. B cells, IgE
The suborder Prosimii includes:a
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A. trematodiases B. human echinococcosis C. lymphatic filariasis D. onchocerciasis E. dracunculiasis