in normal human heart there is no mixing of oxygenated and deoxygenated blood for two mark question

The human heart is four chambered with a distinct division between the two ventricles. unlike amphibians, who have three chambered heart (2 auricles and 1 ventricle), the ventricles of the human heart have an interventricular septum between them which separates the two and prevents the mixing of oxygenated and deoxygenated blood in them.