Final answer:
Yes, a plane through a body part perpendicular to the axis does divide it into upper and lower portions.
Step-by-step explanation:
The question asks whether a plane through a body part perpendicular to the axis divides it into upper and lower portions. This is true. The plane being referred to in this question is the transverse plane. The transverse plane is a horizontal plane that divides the body or organ into upper and lower portions.