Metabolism may have begun when ________ within rocks donated electrons to dissolved carbon monoxide (CO), forming organic compounds
a. oxygen
b. iron sulfide
c. hydrogen gas
d. carbon dioxide
e. ammonia
b
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Bicarbonate ions in the blood can absorb hydrogen ions, keeping pH balanced. Bicarbonate is acting as a ____ in blood.
A. acid B. alkaline C. buffer D. base
An induration of less than 5mm in the Mantoux test is negative for TB.
Answer the following statement true (T) or false (F)
When a neuron is at rest
a. there is a voltage difference across the membrane of about 70 millivolts. b. the interior is negatively charged. c. it is not responding to a stimulus. d. the fluid outside the membrane has more sodium and less potassium than the cytoplasm. e. all of these occur.
The second stage of cellular respiration, ________, takes place only in the mitochondria.
Fill in the blank(s) with the appropriate word(s).