Question

Which of the following is a flightless bird?
A. Aptenodytes
B. Passer
C. Corvus
D. Pavo cristatus

Answer 1

Hint: There are so many birds present on the planet, whereas most of these birds share common features but there are some birds that lost their characteristic features due to their adaptive changes during the process of evolution.

Complete answer:
-Aptenodytes: Aptenodytes genus contains two living species of penguins collectively known as the great penguins as emperor and king penguins. Penguins are a group of aquatic flightless birds but they are better built for swimming and diving.
-Passer: Passer is a genus of sparrows which is also known as the true sparrows. This genus includes the house sparrow and the Eurasian tree sparrow, two of the most common birds in the world. These birds are small with thick bills for eating seeds and are mostly colored grey or brown.
-Corvus: Corvus is a genus of widely spread medium-sized to large birds in the family Corvidae. This genus involves species commonly known as crows, rooks, etc. These are birds with a slender appearance, equipped with a small rounded head with a strong conical beak which is pointed, legs are strong and the tail is short.
-Pavo cristatus: Pavo cristatus is commonly known as Indian peafowl, common peafowl, and blue peafowl which are a peafowl species and native to the Indian subcontinent. Male peacock is brightly colored with a long train while female peacock lack train and are duller brown plumage. Peacock is the national bird of India.

Hence, the correct answer is option (A).

Note: Flying birds have a structure known as a keel, a ridge on the sternum which is absent in flightless birds such as ostrich. But the penguin keel is somewhat retained but it is not used for flight, instead it is useful for flightless aquatic existence.