When reading questions, be careful not to read too quickly. In this case, fast but inefficient reading will lead us to assume that it is asking about ...
<h3> Answer</h3>
alveoli
<h2> Explanation</h2>
During gas exchange oxygen moves from the lungs to the bloodstream. ... This happens in the lungs between the alveoli and a network of tiny blood vessels called capillaries, which are located in the walls of the alveoli.
Mitochondria and chloroplasts likely evolved from engulfed prokaryotes that once lived as independent organisms.
(At some point, a eukaryotic cell engulfed an aerobic prokaryote, which then formed an endosymbiotic relationship with the host eukaryote, gradually developing into a mitochondrion. Eukaryotic cells containing mitochondria then engulfed photosynthetic prokaryotes, which evolved to become specialized chloroplast organelles).
C.
the skeletal muscles are attached to the bones which are partly controlled by the central nervous system.