Which of the following refers to a substance which triggers an immune response?
A) antibody
B) antigen
C) lymphocyte
D) macrophage
B
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What is NOT a contributing factor to the economic downturn of 2009?
A) It is the end of a 40-year growth cycle in the stock market. B) It was the peak of a 30-year commodity cycles. C) Peak oil prices and real estate prices collided with a downturn in the stock market. D) The spending wave of the baby boomers came to an end. E) failure of Americans to innovate after the tech boom of the 1990s
How do scientists estimate the age of the Universe?
A. By measuring speed of light from distant stars B. By measuring the relative motion of other galaxies C. By measuring the age of the oldest known asteroids
Which of the following hydrolyzes proteins only on the amino side of tryptophan, phenylalanine and tyrosine?
A) carboxypeptidase B) chymotrypsin C) trypsin D) none of these
A strong negative index for the North Atlantic Oscillation (NAO) usually means there is ________ of a pressure difference between the Bermuda (subtropical) High and the Icelandic Low pressure. This brings ________ than average temperatures over the northern U.S. and Northwest Europe.
A) less; cooler B) less; warmer C) greater; cooler D) greater; warmer