Final answer:
Spider silk is found in nature, while Kevlar is a synthetic polymer.
Step-by-step explanation:
Spider silk and Kevlar have several properties in common, such as tensile strength and flexibility. However, one property that is not shared by Kevlar is that spider silk is found in nature while Kevlar is a synthetic polymer. Spider silk is produced by spiders in their silk glands, whereas Kevlar is a man-made material created through chemical synthesis.
This difference in origin is an important feature of spider silk because it allows spiders to readily produce and repair their webs in their natural environment. On the other hand, Kevlar's synthetic nature makes it more suitable for specific applications where its high tensile strength is required, such as body armor and bulletproof vests.