The following are a set of characteristics found in the animal kingdom:
A. The body is usually streamlined. Some have spindle-shaped or elongated body.
B. The body is covered with thick-seated scales, which provides protection to the internal organs.
C. They may be herbivores or carnivores, oviparous or ovoviviparous.
D. The nervous system comprises of the brain and ten pairs of the cranial nerves.
E. All of them are oviparous and exhibit sexual dimorphism.

Select the correct set of characterizing features for the Class Pisces.

Correct option is D

Explanation-

​Pisces (fishes) are cold-blooded aquatic vertebrates. We must identify which of the statements A–E are characteristic features of this class.

Statement A -  "The body is usually streamlined. Some have spindle-shaped or elongated body."
True
Streamlined bodies reduce resistance in water. Fishes often have fusiform (spindle-shaped) or elongated bodies for swimming efficiency.

Statement B -  "The body is covered with thick-seated scales, which provides protection to the internal organs."
True
Fishes have dermal scales (like placoid, ganoid, cycloid, or ctenoid), which serve as protection and help reduce friction.

Statement C -"They may be herbivores or carnivores, oviparous or ovoviviparous."
True
Fishes exhibit dietary diversity: some are herbivorous (e.g., parrotfish), others carnivorous (e.g., sharks). Most fishes are oviparous, but some are ovoviviparous (e.g., guppies, sharks).

Statement D -  "The nervous system comprises of the brain and ten pairs of the cranial nerves."
True
Fishes have 10 pairs of cranial nerves, unlike mammals which have 12.

Statement E - "All of them are oviparous and exhibit sexual dimorphism."
False
Not all fishes are oviparous. Some are ovoviviparous or even viviparous. Sexual dimorphism is not seen in all fish species (some show it, others don’t). So, this is an overgeneralization.

Correct Statements: A, B, C, and D

Correct option is d - A, B, C and D.