Direction: Do as directed for the question.
Researchers pushing the limits of optical design are learning from a simple sea creature crusted with tiny lenses, each one smaller and more perfect than any human engineer could devise. The brittlestar, as the organism is called, sees with its bones. Built into the starfish’s tough, calcite skeleton are arrays of microscopic crystals that focus light ten limes more precise than any manufactured micro-optics. Each brittlestar lens is one-thousandth of an inch across, composed of a calcite crystal that grows into a flawless eyepiece naturally corrected for any distortions, double images or any other optical aberrations. The beadlike lenses cover skeletal plates on the brittlestar’s five supple arms and its disk-shaped body. What is the purpose of the passage?