Pigs are more closely related to the human than birds and fishes.
<h3><u>Explanation</u>:</h3>
Development of brain is a very interesting and important marker to evaluate evolutionary relationships between the species. Brain is most complex organ of an animal's body and with evolution, it becomes more and more complex.
If we see into fish brain, we will see more simpler structures with only 10 cranial nerves. But with evolution as the birds came, it was more complex. But it was nowhere near with humans.
With the pigs, we can relate the level of complexity and the structures of brain along with the skull to cranium ratio much matching with that of humans.
So pigs are much more related to humans than others.
This is also evident that although all are chordates, the fishes belong to class Pices, birds to Class Aves and both pig and human to class Mammalia.
