The first cells probably arose about
A. 500 million years ago.
B. 1.2 billion years ago.
C. two billion years ago.
D. six billion years ago.
E. four billion years ago.
Answer: E. four billion years ago.
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Heavy metals are effective antimicrobial agents but are not widely used because of their high toxicity to humans.
Answer the following statement true (T) or false (F)
Oil spills are sprayed with bacterial cultures in order to
A) prevent the oil from sticking to wildlife. B) kill the bacteria. C) detoxify the oil. D) break down the oil. E) make the oil easier to wash away.
Regardless of its shape, a given orbital may contain no more than
A. 2 electrons. B. 4 electrons. C. 1 electron. D. 8 electrons.
With gene therapy being at the cutting edge of medical technologies, it is not surprising that serendipitous treatments are discovered. Explain how treating an HIV-positive patient with stem cells from an HIV-resistant donor cured him or her of HIV while
targeting his or her acute myeloid leukemia. What will be an ideal response?