The triangular sac like structure which receives blood through the vena cava in frog is
Which of the following structure is absent in rabbit's heart

Options

A. Ventricle
B. Sinus venosus
C. Hepatic portal system
D. Left auricle

Answer

B

Explanation

Sinus venosus is the first chamber of the heart in fish, amphibia and reptiles. In fish it receives blood from the cuverian ducts and hepatic veins and leads into the single auricle. In amphibians and reptiles it receives blood from the three vanae cavae and leads to the right auricle. Birds and mammals have no sinus venosus.