Step 1: Recall Garbhaja Bhava.
Classical embryology attributes different features of the developing fetus to different contributing factors, called Garbhaja Bhava
Step 2: Recall Rasaja Bhava.
Rasa, the nutrient fluid from the mother, is said to contribute growth, strength and complexion to the fetus
Step 3: State the answer.
So Upachaya, Bala and Varna fall under Rasaja Bhava
\[ \boxed{Rasaja Bhava} \]