Protons and Carbon Dioxide Are Linked in the CNS Because

Multiple Choice

Protons and carbon dioxide are linked in the CNS because

A) protons cannot cross the blood-brain-barrier, while carbon dioxide can.
B) carbon dioxide cannot cross the blood-brain-barrier, while protons can.
C) bicarbonate cannot cross the blood-brain-barrier, while protons can.
D) protons cannot cross the blood-brain-barrier, while bicarbonate can.
E) water cannot cross the blood-brain-barrier.