Earth formed about ___________ years ago, and the oldest known living organisms date to ___________ years ago.

A. 4.6 billion years ago ... 3.5 billion years ago
B. 6,000 years ago ... 6,000 years ago
C. 13.7 billion years ago ... 4.6 billion years ago
D. 3.9 million years ago ... 2.0 billion years ago


A. 4.6 billion years ago ... 3.5 billion years ago

Biology & Microbiology

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Why aren't ferns commonly found in deserts?  

A.  Fern fronds are sensitive to UV light. B.  Fern spores are unable to resist prolonged dry conditions. C.  Ferns are non-vascular and cannot absorb water from deep within the soil. D.  Fern pollen is spread by insects that do not occur in deserts.

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Escherichia coli O157:H7 is primarily associated with which of the following foods?

A) ground beef B) dairy products C) eggs D) fomites E) pork

Biology & Microbiology

All of the following are true of chronic fatigue syndrome EXCEPT

A) it may have a genetic component. B) it is also known as myalgic encephalomyelitis. C) it is a psychological disorder. D) it often begins with flu-like symptoms that do not go away. E) it may be triggered by a viral infection.

Biology & Microbiology

In Drosophila, a cross between M males and P females is fertile because

a. P elements are inherited maternally. b. males produce a repressor protein. c. P elements are not expressed in females. d. egg cytoplasm contains a protein that suppresses transposition. e. P elements are nonautonomous.

Biology & Microbiology