What is the evidence for the impurity of human and animal blood and animal carcasses, and what is the correct opinion on this, and which should be followed?

Flowing blood is impure (najis) by scholarly consensus, and explicit proofs for this are found in the Quran and Sunnah. In the Noble Quran: "Say, 'I find not in that which has been revealed to me anything forbidden to be eaten by an eater except that it be a dead animal or blood poured forth or the flesh of swine — for indeed, that is defilement.'" And in the Sunnah, there is the hadith of Asma bint Abi Bakr concerning how to deal with menstrual blood. This ruling is agreed upon by the Companions, the Tabi'un (followers), and the four Imams. Many scholars have transmitted the consensus on the impurity of large quantities of blood.