A Swim Bladder is not present in cartilaginous fishes. Also called a fish maw or gas bladder the swim bladder is a gas-filled bladder that allows many bony fish to control their buoyancy by filling or releasing gas form the bladder. This allows them to change bouyancy without wasting metabolic energy by swimming.
True, you cant always have the ideal conditions in the real world
Answer: The correct answer is- Archaea and Eukarya.
As per the information about the (phylogenetic tree) given in the question,
the last branch of the phylogenetic tree begins with the line of Eukarya and then holds the species of the Archaea division, which includes those prokaryotic organisms that live in extremely harsh environmental conditions ( such as Methanobacterium, and extreme halophiles).
As this last branch holds species of two domains ( from 3 domain system of classification that includes Bacteria, Archaea, and Eukarya) , which are Archaea and Eukarya as it begins with Eukarya and later on holds the species of Archaea.
Thus, it shows that Archaea and Eukarya are more genetically related.
