Which organisms are classified as Aves?

Correct — C. Aves is the vertebrate class of birds, which is option (c).

The class is marked by feathers, forelimbs modified into wings, a toothless beak and pneumatic, air-filled bones. Birds are warm-blooded, have a four-chambered heart, breathe through lungs assisted by air sacs, and lay hard-shelled eggs.

Each of the other options names a different vertebrate class, so the item is a straight match of a Latin class name to its group.

Why the others are wrong

• (a)
  Frogs — Frogs belong to Amphibia — moist skin, an aquatic larval stage, a three-chambered heart, and breeding that depends on water.
• (b)
  Snakes — Snakes belong to Reptilia — dry scaly skin, cold-blooded metabolism, and eggs with a leathery shell laid on land.
• (d)
  Fishes — Fishes fall under Pisces — cold-blooded aquatic vertebrates that breathe through gills and have a two-chambered heart.

Vertebrate classes are separated by a small set of characters: skin covering, mode of respiration, number of heart chambers, control of body temperature, and how the young are produced.

Aves carry feathers, lungs with air sacs, a four-chambered heart, warm blood and hard-shelled eggs. Mammalia share the warm blood and the four-chambered heart but have hair and mammary glands and mostly bear live young.

Reptilia and Amphibia are cold-blooded with three-chambered hearts, the crocodile being the reptilian exception.

Key facts

• Aves is the vertebrate class made up of birds.
• Birds are warm-blooded, have a four-chambered heart and lay hard-shelled eggs.
• Bird forelimbs are modified into wings and their bones are pneumatic, or air-filled.
• Frogs belong to Amphibia, snakes to Reptilia and fishes to Pisces.

Common traps

• Confusing Aves with Amphibia because both begin with the same letter.
• Assuming every warm-blooded animal is a mammal, when birds are warm-blooded too.

No directly related past PYQ was found.