Question

Which of the following is incorrect in case of a ray fish?
A. body is flattened dorsoventrally
B. Gills are situated on the ventral side of the body.
C. Ray fish is a surface feeder.
D. Disc like the body is present.

Answer 1

Fish is an aquatic animal which bears gill for their respiration and lack limbs. They belong to phylum Chordata and majorly fishes divided into cartilaginous fishes and bony fishes. Fishes are one of the superclasses of Gnathostomata and the superclass is Tetrapoda.

Complete answer:
Pisces includes true fishes that are divided into three classes such as Placodermi (armored fish), Chondrichthyes (Cartilaginous fish), and Osteichthyes (Bony fish).
Ray fish is cartilaginous fish belonging to Chondrichthyes class, which is cold-blooded and identified by its flattened body with enlarging pectoral fins which are fused with head and gills slits that are placed on the ventral side. These rays fishes are bottom dwellers or found on the seafloor and feed on snails, oysters, small fishes, and crustaceans example:- electric ray, stingray, and sawfish.
The bony fishes are called Osteichthyes fishes they are found in all types of water such as fresh, marine, and brackish water, the majority of this class fishes does not possess fused fins and presents on ventral, dorsal, pectoral, pelvic and tail region. Such body fishes have to streamline the body, which provides speed in water and feeds on other fish crustaceans. They are usually surface feeders they prey on other fishes.
Hence, the correct option is C.

Note: Fishes have a spindle-shaped elongated body and its body is distinguished into the head, trunk, and tail, with paired or unpaired fins which represent the appendages on the body and its body is covered by scales with slimy fluid, which protect from desiccation.