when I hugged my dad who had just returned from the city where he served because my dad was a soldier who served outside the city and rarely came home
:v
The heart begins very early in mesoderm within the trilaminar embryonic disc. The heart forms initially in the embryonic disc as a simple paired tube inside the forming pericardial cavity, which when the disc folds, gets carried into the correct anatomical position in the chest cavity.
I think the circulatory system is the best body system because we need the heart to stay alive, many people live with only one lung. but we need the respiratory system to let oxygen in, and let carbon dioxide out.
I think it might be A but I'm not sure
