Answer:
alveoli
Explanation:
because carbon dioxide moves from the blood in the capillaries to the air in the alveoli
Hey there!
There is a window period between being exposed to HIV and getting accurate results as to whether or not you have actually been infected. Many HIV tests can detect an infection two to three weeks after initial exposure. If someone tests negative on many HIV tests after two weeks since the possible exposure, they're likely HIV-negative, but should still get tested after a certain amount of additional time since everyone can react to the infection differently.
Your answer will be your second option.
Hope this helped you out! :-)
