Multicellular organisms arose because a part could die and be removed and the organism could continue to live. they could eat unicellular organisms unicellular organisms began to die off with the oxygen-filled atmosphere

Multicellular organisms arose because a part could die and be removed and the organism could continue to live.

Explanation:

The first organisms that emerged were unicellular beings with a very simple organization. Later for several reasons, these early organisms began to unite until their level of organization became quite complex, forming multicellular organisms. Multicellular organisms arose because a part could die and be removed and the organism could continue to live.

The first specimens of multicellular organisms were observed about 3 billion years ago, and were similar to cyanobacteria that can be found today. However, due to the absence of rigid structures, these organisms were not preserved in the fossil record, making it difficult for researchers to determine their true appearance.

Some researchers believe that the evolution of unicellular organisms until the emergence of multicellular organisms occurred multiple times and not only once, having occurred by different processes, these changes have been suffered in different clades, giving rise to quite different beings.

The differentiations that gave rise to multicellular beings were not always divergent, in some cases convergent, since the changes that these organisms underwent, although individual, gave rise to similar individuals, or those with similar characteristics.

fumikage isn't really a bird, and tsuyu does have teeth. tsuyu has a transformation quirk which still allows her to be partially human. otherwise we'd have a large frog running around. fumikage has teeth because again, he isn't a bird. his head was a quirk mixture if i'm correct.