ameoba
They are, indeed, the most simplest multi-cellular marine animal
Cats
dog
the most ancient sea mammal would have to be the flat fish although it is endangered.
Organism.
cells < tissue < organs <organ systems
The oldest known and simplest organisms are part of the Archaebacteria kingdom. Members of this kingdom are one celled organisms and are also the most ancient organisms.
ancient egyptians used animal fat.
the animal that osiris wore on his head in ancient Egypt the animal that osiris wore on his head in ancient Egypt
There isn't any official animal to represent ancient Egypt, but I would think the Sphinx.
The donkey which was the farm and transportation workhorse, or perhaps the ferret (commonly miscalled as cats)..
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