Final answer:
The two major branches of the right coronary artery are the marginal arteries, which supply the right ventricle, and the posterior interventricular (posterior descending) artery, which supplies the interventricular septum and both ventricles.
Step-by-step explanation:
The right coronary artery has two major branches that serve different parts of the heart. The marginal arteries, which usually arise inferior to the right atrium, supply blood to the superficial portions of the right ventricle. The other important branch is the posterior interventricular artery, also known as the posterior descending artery, that runs along the posterior portion of the interventricular sulcus toward the apex of the heart. This artery provides branches that supply the interventricular septum and portions of both ventricles.