Why Do Some People Have Curly Hair and Others Have Straight?

Hair is like a rope made of tiny threads called keratin. When your hair grows, the shape of these threads decides if it will be curly or straight. If your hair has a rounder thread, it’s more likely to curl up. If it's flatter, it stays straight. Just like how a rope with rounded strings looks wavy, and one with flat strings is smoother.

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Examples

Imagine your hair is like a piece of string, if it’s round, it stays straight; if it's oval, it curls up.
Your curly-haired cousin gets that from their parents who both have curly hair, while you got straight hair from your mom and dad.
If you look closely at a strand of your hair under a magnifying glass, straight hair looks like a circle, while curly hair looks more like an oval.

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Categories: Biology · hair types· genetics· biology· heredity· curly hair