When considering the preservation of a lens from a cow eyeball dissection kit for long-term demonstration purposes, it is essential to understand its composition and the best storage methods. The lens is primarily made of crystallin proteins, which are stable and do not degrade over the organism's lifetime. For preservation, fixation with chemicals like formaldehyde is not recommended, as it can distort the lens and affect its ability to demonstrate light refraction. Instead, storing the lens at room temperature or around 37°C is advised, as cold temperatures can denature the proteins and damage the lens. Proper storage without fixation will help maintain the lens's integrity for over five years.