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

Biology & Microbiology

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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

Biology & Microbiology

An induration of less than 5mm in the Mantoux test is negative for TB.

Answer the following statement true (T) or false (F)

Biology & Microbiology

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.

Biology & Microbiology

The second stage of cellular respiration, ________, takes place only in the mitochondria.

Fill in the blank(s) with the appropriate word(s).

Biology & Microbiology