Approximately when did the earth's crust solidify?
A. 8 billion years ago
B. 1 billion years ago
C. 4 billion years ago
D. 4 million years ago
Answer: C
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What are the products of one turn of the Krebs cycle?
A. 1 CO2, 2 NADH, 1 FADH2, 1 ATP B. 2 CO2, 3 NADH, 1 FADH2, 1 ATP C. 2 CO2, 6 NADH, 2 FADH2, 2 ATP D. 4 CO2, 6 NADH, 2 FADH2, 2 ATP E. 4 CO2, 12 NADH, 4 FADH2, 4 ATP
Some people can detect PTC, a bitter compound found in broccoli and Brussels sprouts, whereas others cannot. Which of the following is the most likely explanation for this observation?
A. The G protein pathway that alters the conformation of the sodium channels is defective. B. Chemoreceptors specific for PTC are not expressed. C. Too few sodium channels are present in the taste receptors. D. Neurotransmitter release from these taste receptors is impaired.
Which is another name for bone cells that remain alive even after the extracellular matrix becomes hardened with calcium phosphate crystals?
A. Fibrocytes B. Leukocytes C. Osteocytes D. Chondrocytes E. Erythrocytes
Lactose, the sugar in milk, is a _______, because it can be split into two monosaccharides.
Fill in the blank(s) with the appropriate word(s).