What is the term for the degree to which the external form of an organism can be divided into mirrored halves?

The term for the degree to which the external form of an organism can be divided into mirrored halves is called bilateral symmetry. Bilateral symmetry refers to a specific arrangement of body parts where the left and right sides of an organism are mirror images of each other. This type of symmetry is commonly observed in many animals, including humans, where the body can be divided into two identical halves along a single plane, typically the sagittal plane.

In contrast, organisms exhibiting radial symmetry can be divided into similar sections around a central axis, like jellyfish or starfish. The concept of symmetry in biology is vital for understanding the structure and function of organisms, influencing their movement, reproduction, and evolutionary adaptations. Bilateral symmetry often allows for streamlined movement and better coordination, which can be advantageous for predation or escape from predators.