The correct answer is absence of jaws.
Lampreys and hagfish are in the class Agnatha, they are jaw-less fish. The members of the agantha class are probably the earliest vertebrates. Scientists have found fossils of agnathan species from the late Cambrian period that occurred 500 million years ago.
The lack of access to the healthy food has caused the growth of Sebastian to slow down. In the case healthy food is provided to him, he can grow into the size he was genetically suited to. This process is known as the canalization. Canalization term is used as the measure of the ability of any given genotype to result in the same phenotype in-spite of the environmental variability.
I believe the answer might be A
Prokaryotes, which the most common type of prokaryote is a bacteria