Question

Large and well developed sternum with keel in a bird suggest
A) Inability to fly
B) Fast running adaptation
C) Strong flying ability
D) Fast swimming adaptation

Answer 1

Hint:In bird anatomy, the keel or carinae is an extension of the sternum that runs axially along the midline of the sternum and extends outward, perpendicular to the ribs' plane.

Complete answer:
One of the main bones in the body of a bird is the breastbone or sternum, which is part of the pectoral girdle. It consists of a basal convex / concave plate and, protruding ventrally, the keel perpendicular to it.
In the anatomy of tetrapods (four-limbed vertebrates), the sternum, also called the breastbone, is an elongated bone in the middle of the chest that articulates and protects the clavicles (collarbones) of the shoulder girdle and the ribs. Its evolutionary origin is unclear.

In certain salamanders, a sternum appears; it is present in most other tetrapods but lacks legless lizards, snakes, and turtles (in which the shell provides the support needed). An expanded keel, to which flight muscles are connected, arises in birds; the bat's sternum is also keeled as a flight adaptation.
Where the strong flight muscles connect to the body is the keel-shaped sternum (breastbone). The total number of bones in birds is less than in mammals or reptiles. This is because they have fused many of their bones together to make the skeleton more rigid.

Thus the correct answer is option (C) Strong flying ability.

Note:Historically, as a broad classification of birds into two orders, the presence or absence of a pronounced keel structure was used: Carinatae (from carina, 'keel'), having a pronounced keel; And ratites (from ratis, 'raft' referring to the flatness of the sternum), providing a subtle arrangement of the keel, or totally missing one.However, as genetic studies have shown that many flightless birds have evolved from flighted birds, this classification has fallen into disuse.