Answer:
Invertebrates have a very quick life cycle and die very easily, as a result, they evolve very quickly into many different types of animals. also, they are often very small and their ecosystems are subject to much quicker change than that of vertebrates, meaning that mutations in their genes become relevant more often. Many invertebrates span very large areas (sea animals span most of the oceans, insects span entire continents) and so they evolve to be different species in different places.
Or
They do not have bones, they live on water or land, they can have soft bodies or exoskeletons, and others are parasites.
The answer you are looking for is Collagen.
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It’s the first one!
compact bone is a dense bone with a bony matrix that is solidly filled with arya if ground substance and inorganic salts, leaving only tiny spaces (lacunae) that contain osteocytes, or bone cells. Immature compact bone DOES NOT CONTAIN OSTEONS and has a woven structure.
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