Final answer:
The dividing of the body into a top and bottom portion is done along the transverse plane (option b) , which can also be referred to as a cross-section.
Step-by-step explanation:
If the body is sliced so the result is a top and bottom portion, this is referred to as the transverse plane. A transverse plane, or horizontal plane, divides the body or organ horizontally into upper and lower portions. It's sometimes described using the term cross-section, especially when a body or anatomic structure is sliced along this plane for medical imaging or anatomical study.
The midsagittal plane is different, as it cuts the body into equal right and left halves. On the other hand, the body's midline is a physical line that indicates the center of the body or organ but does not represent an actual slice or section. Therefore, the correct answer to the student's question is b) transverse plane.