The answer is B. They bring oxygen from the air into the body.
The lungs don’t produce or release oxygen so it’s not A. or D. The lungs do not transform oxygen into carbon dioxide cause our bodies need oxygen not carbon dioxide so it’s not C. Hope this helps!
Lymphedema is the condition I believe.
C. Protons and electrons must be equal as protons have a + charge and electrons are - so they cancel out
"The red blood cell<span> survives on average only 120 days. </span>Red cells<span> contain a special protein called hemoglobin, which helps carry oxygen from the lungs to the rest of the </span>body<span> and then returns carbon dioxide from the </span>body<span> to the lungs so it can be exhaled." - hematology.org</span>
