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Answer:
Because some have another way to hold their bodies up and protect their internal organs, and therefore they don't need bones.
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The ones who don't have internal skeletons/bones are called Invertebrates. This group includes more animals than those who are Vertebrates (who do have internal skeletons with backbones, like us and other mammals). Invertebrates make up over 90% of the Earth's animal lifeforms, so more animals don't have bones than do.
Invertebrates include insects who don't need an internal skeleton because they have an exoskeleton (for example, a hard coat, like a Ladybug wears) that protects and supports their organs. There are also sea animals like oysters and conch that are invertebrates with shells to protect them. Other invertebrates do this with other and unusual methods that are fun to learn about.
See the related questions below for more information about vertebrates and invertebrates.
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∙ 13y ago
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Do all animals have muscles?
All animals that are multicellular organisms have muscles.
Do animals with closed circulatory systems have bones?
All animals have bones.
How many bones are there in animals?
Depends on the animal- there is no one answer. Unless you want to say that ALL bones are in animals.
Do elephant have bones?
Yes they do all animals have bones except for worms.
Do toblins have back bones?
they dont have back bones they dont have back bones they dont have back bones they dont have back bones
Does grass have a backbone?
No, they do not have a backbone, they have an exoskeleton.
What is a part of an animals endoskeleton?
All its bones.
Does octopus have backbones?
aren't they invertibrates? meaning they have no bones or watever...
What bones do all animals have in common?
Teeth because all animals need to chew their food.
Where do animals with back bones live?
All over the place, it's the group of animals we see most often. All 4-legged animals have backbones. All birds and snakes for instance have back bones.
What are all the bones in an organism called?
i dont know
What is all the bones in an organism called?
dont care
