Final answer:
Symmetry involves a balanced arrangement of similar parts on opposite sides of a central line, evidenced in nature by examples such as a butterfly's wings, which exhibit striking symmetry.
Step-by-step explanation:
Symmetry refers to the proportionate and balanced arrangement of similar parts of an object or organism on opposite sides of a dividing line or median plane. In nature, this proportional balance is widely observed. An impeccable example of symmetry in nature is a butterfly's wings, which show a strikingly symmetrical pattern. Additionally, the human body showcases bilateral symmetry, which means that the body can be divided into left and right halves that are mirror images of each other.
Furthermore, the symmetry we observe in biological structures extends to our senses, contributing to our perception of what is aesthetically pleasing or balanced. This emphasis on symmetry can also be seen in advanced fields such as particle physics, where research at facilities like CERN's Large Hadron Collider examines the symmetrical properties of sub-atomic particles.