Which one of the following organisms bears hollow and pneumatic long bones ?

The correct answer is Neophron.

Let us break down the anatomical characteristics described in the question step-by-step to understand why this option is correct:

1. Understanding Pneumatic Bones: Pneumatic bones are hollow bones containing air cavities (air sacs). This specialized adaptation reduces overall body weight without sacrificing structural strength, which is essential for flight.
2. Identifying the Group: Hollow and pneumatic long bones are a characteristic feature of birds (Class Aves).
3. Analyzing the Options:
   • Neophron: Commonly known as the Egyptian vulture, it belongs to the Class Aves (birds). Therefore, it possesses hollow and pneumatic long bones to facilitate flight.
   • Hemidactylus: Commonly known as the wall lizard, it belongs to the Class Reptilia. Reptiles do not have pneumatic bones.
   • Macropus: Commonly known as the kangaroo, it is a marsupial mammal belonging to the Class Mammalia. Mammals have solid bones containing bone marrow.
   • Ornithorhynchus: Commonly known as the platypus, it is an egg-laying mammal belonging to the Class Mammalia, and thus does not possess pneumatic bones.