Biology · STRUCTURAL ORGANISATION IN ANIMALS

Identify the true anatomical statement regarding the heart chambers and accessory chambers in a frog:

1. The heart has two ventricles and one atrium completely enclosed within a double-layered pleura.
2. The sinus venosus joins the left atrium, while the conus arteriosus arises from the dorsal aspect of the right atrium.
3. A triangular sinus venosus opens into the right atrium, and the ventricle opens ventrally into the conus arteriosus.
4. Deoxygenated blood from the vena cava drains directly into the single ventricle bypassing both atria.