i Register
In some senses, carapace is marked as figuratively. Watch for register when choosing this word.
noun
A hard protective covering of bone or chitin, especially one which covers the dorsal portion of an animal.
That which protects.
So, little by little, youth loosens the hard carapace of confining custom their elders have built over the human heart.
This is all a massive failure of science to pierce the carapace of public ignorance.