Chitin, a protein similar to keratin which is what that fingernail you have lodged in your nostril is made of.
Their exoskeleton made out of the structural polysaccharide "chitin" (i.e. a sugar polymer).
a grasshoper sometimes moves slow and fast.
The exoskeleton composition did not change through time in trilobites. Trilobites maintained a calcite exoskeleton throughout their existence in the fossil record.
grasshoper
they hop
no.
it dies.
grasshoper
they have exoskeleton
birds humans mice
in the ground(grass)
DNA test.