Which structure separates the right and left ventricles?

A) Chordae tendineae
B) Right ventricle
C) Right atrium
D) Interventricular septum

Interventricular Septum

The thick wall separating the lower chambers (ventricles) of the heart, preventing oxygen-rich and oxygen-poor blood from mixing.

Chordae Tendineae

Heart strings, or tendinous cords, that connect the papillary muscles to the tricuspid valve and the mitral valve in the heart, preventing inversion.