Capillary walls are only one cell thick, so oxygen can pass out of the blood, and waste material can pass into the blood.

What happens to the hematocrit/hemoglobin levels in a pregnant female?

A) Hemoglobin increases, hematocrit decreases. B) They don't change. C) Both increase. D) Both decrease.

The sympathetic nervous response causes which of the following to occur?

A) Breathe faster and deeper, blood vessels to constrict, heart to beat stronger and faster, skin to sweat, pupils to dilate, and skin to become pale B) Breathe faster and deeper, blood vessels to constrict, heart to beat stronger and faster, skin to sweat, pupils to constrict, and skin to become warm C) Breathe faster and deeper, blood vessels to dilate, heart to beat stronger and slower, skin to sweat, pupils to dilate, and skin to become pale D) Breathe slower and deeper, blood vessels to dilate, heart to beat stronger and faster, skin to sweat, pupils to constrict, and skin to become pale