Question

Aortic arch $IV$ is represented by a single systemic aorta arising from left in

• A. reptiles
• B. birds
• C. mammals
• D. both $1$ and $2$

Answer 1

Answer: (C)

In a typical vertebrate embryo, a ventral aorta, a dorsal aorta and usually $6$ pairs of aortic arches connecting ventral aorta with dossal aorta are present. They modify in adults mainly because of a shift from gill respiration to lung respiration. The number of aortic arches undergoes a progressive reduction in number from lower to higher vertebrates. Arch $IV$ is represented by a single systemic aorta, right in birds and left in mammals. In reptiles, fishes and amphibians it is paired.