Assertion: A thick fibrous tissue called AV septum separates the atrium and ventricle of same side.
Reason: Each of these septa are provided with an opening through which the two chambers of the same side are connected.
Hello Riddhi, please refer to the following link below:
https://learn.careers360.com/medical/question-the-atrium-and-ventricle-of-same-side-are-also-separated-by-a-thick-fibrous-tissue-calledoption-1-mitral-valve/