Final answer:
The bulbus cordis is the primitive part of the heart that develops into the right ventricle during embryogenesis.
Step-by-step explanation:
The primitive area of the heart that will give rise to the right ventricle is the bulbus cordis. During embryonic development, a single primitive heart tube forms from the fusion of the endocardial tubes. This heart tube then differentiates into five distinct regions. Among these, the bulbus cordis develops into what will become the right ventricle, playing a critical role in the development of the heart's structure and function. On the other hand, the truncus arteriosus is responsible for giving rise to the ascending aorta and pulmonary trunk, and the sinus venosus develops into structures including the posterior portion of the right atrium, the SA node, and the coronary sinus.