Question

Carapace occurs in
A. Toad
B. Frog
C. Bird
D. Tortoise

Answer 1

Hint: The skeleton aids in movement, locomotion and muscular development in the organisms. It can be either present externally and internally. Some organisms possess an external or internal skeleton only while some may possess both of them. All vertebrates from the amphibians, fishes, reptiles, birds and mammals contain an internal skeleton known as exoskeleton while most of the invertebrates lack an internal skeleton but contain an external skeleton.

Complete step by step answer: An internal skeleton present inside the body of an organism is known as endoskeleton. All the vertebrates possess an endoskeleton which is a body or cartilaginous structure. The external skeleton that is present outside the body of an organism forming a hard covering. The hard covering protects the soft body of the organisms. A carapace is a dorsal portion of the skeleton or exoskeleton present in a number of animal groups. It is present both in the vertebrates and invertebrates. In the vertebrates carapace is present in turtles and tortoises. The carapace forms the convex of the cell structure of a turtle's covering. it consists of the animal’s rib cage, dermal armor and scutes.
Turtles belong to the order Testudines and are reptiles that are characterized by the presence of a special body and cartilaginous shell. The upper shell is called the carapace while the lower portion of the shell that covers the belly is called plastron. Both the plastron and carapace are joined on the sides by a body structure known as the bridges.
The inner shell is made up of several bones that contain part of the back bone and the ribs. In most turtles, the outer layer of the shell is covered by a horny scale known as the scutes. The scutes are made up of fibrous proteins or Keratin. Keratin is an important component found in the scales of the reptiles. The scutes overlap the area of the seams present between the shell bones and it functions to add strength to the scutes. In some species of turtle and tortoises, horny scouts are not present but have shells that are covered with leathery skin.
Frogs and toads belong to the amphibian class and are animals that are able to live both on the land as well as in the water. They have a slimy and mucus skin but do not contain a carapace.
Birds are characterized by their ability to fly due to the modification of the forearm into wings and presence of light bones and feathers.
Therefore, the correct option is option D.

Note: Tortoise are reptiles that are exclusively characterized due to the presence of carapace. The carapace is also known as a shell. They are either made up of a bony or leathery skin. The shell is developed from their ribs and it acts as a shield. as the inner shell layer is mostly made up of parts of the backbone and ribs of the body, the turtles cannot crawl out of its shell.