The laws that relate to purity/impurity of man follow those of animals as was the order during creation. Maskil L'Dovid: Why does Rashi (and Rav Simlai) feel that the order is in need of explanation (Rashi doesn't always explain the סמיכות הפרשיות)? Why does he save this question for the beginning of Tazria rather than the beginning of Vayikra?
Why does the Torah conclude the parsha of korbanot (זאת תורת היולדת) brought after childbirth before listing the korban for one who can't afford the standard korban?
When introducing the parsha of the metzora (Vayikra 13:1) why is the usual phrase "דבר אל בני ישראל" absent? Tanchuma - usually the ultimate goal of a mitzvah is for it to be fulfilled, the ultimate goal here is for it never to be necessary!
Why is the order in which the types of tzaraat are presented in the chumash (person, clothing, house) the opposite of the order in which it occurs?