Question

Urinary bladder is absent in
A) Aves
B) Reptiles
C) Amphibians
D) Mammal

Answer 1

Urinary bladder is defined as a muscular sac present inside the pelvis or above or beneath its pubic bone. When it is empty, it acquires the shape and size of the pear.

Complete answer:

Option A:-The birds do not show any presence of the urinary bladder. Therefore, this is the correct option.
In birds, they have a single pathway to excrete substances and that is cloaca. Through cloaca, mixture of both fluids and materials are excreted.
Option B:- All the reptiles show the presence of their urinary bladder producing hypoosmotic urine that shows the presence of nitrogenous wastes such as uric acid. This uric acid easily undergoes precipitation. Therefore, this is the incorrect option.
Option C :-The urinary bladder of amphibian is a bilobate, vascularised, and highly distensible sac storing liquid for regular use throughout the phase of water stress. Therefore, this is the incorrect option.
Option D:-All mammals show the presence of a urinary bladder which begins from their embryonic cloaca and eventually gets differentiated within a dorsal part connected through its intestine and a ventral part which later associates with its urogenital passage. Therefore, this is the incorrect option.

Thus, the correct alternative to the given question is Option A) Aves.

Note: The urinary bladder represents a hollow muscular organ of all the vertebrates that is responsible for storing urine in the kidneys before it undergoes a process of urination. A typical human urinary bladder is responsible for holding urine between 300 to 500 ml.