Which plane divides the body or organ vertically?

The sagittal plane is the correct answer because it is defined as a vertical plane that divides the body into right and left parts. This plane runs parallel to the midline of the body and can be positioned at any point along the body. When it is specifically at the midline, it creates equal right and left sections, which is often referred to as the midsagittal or median plane.

In contrast, the frontal plane (also known as the coronal plane) divides the body into anterior (front) and posterior (back) sections, which is a different orientation entirely. The horizontal plane (or transverse plane) separates the body into superior (upper) and inferior (lower) parts, typically cutting across the body horizontally. Thus, while each of these planes serves a specific purpose in anatomical studies and descriptions, the sagittal plane uniquely fulfills the requirement of dividing the body vertically into right and left sections.