The organism which is least related to the other three organisms is second. This is because the more the similarity of amino acid sequence, the more is the organism related.
What do you mean by Organism?
An Organism may be defined as a living thing made up of one or more cells and able to carry on the activities of life.
In the given figure, the amino acid sequence SER is present in all the organisms, LEU is not present in organism 2 and ASN is the only amino acid sequence that is present only in organism 2.
Therefore, the organism which is least related to the other three organisms is second.
To learn more about Amino acid sequence, refer to the link:
https://brainly.com/question/17295633
