Lower l/3rd of anal canal is derived from-
Proctodaeum
Cloaca
Urogenital Sinus
Midgut
Ans. is 'b' i.e., Proctodaeum * 'The lower third of the anal canal is an ectodermal derivative and is derived from the proctodaeum.'* Part of anal canal above pectinate line develops from dorsal part of endodermal cloaca (primitive rectum) and part of anal canal below pectinate line develops from ectodermal proctodeum.
Abdomen & Pelvis