Question

Which one of the following is a true fish?
A) Silverfish
B) Flying fish
C) Crayfish
D) Whale

Answer 1

Hint: Fishes, as we know, are aquatic animals which cannot survive without water. The major characteristics of a fish is having fins, a gill or pair of gill slits and tail to help in swimming. Other creatures or animals residing in water also can look like a fish but the true characters are defined by this. Dogfish is known as a true-fish.

Complete answer:
Option A silver fish- silver fish are none-other than dog fish which are considered as a true fish having all the characteristics a fish has.
Option A is the correct answer.
Option B Flying fish- flying fish as the name suggests have wings and tail instead of fins. Their fins are modified to look like wings. They belong to the class Actinopterygii.
Option B is not the correct answer.
Option C Crayfish- crayfish are crustaceans representing the lobsters. They have a tail longer compared to the body and with no fins. Examples can be- mudbugs, mountain lobsters, freshwater lobsters.
Option C is not the correct answer.
Option D Whale- whale is not a fish. Whales are mammals found in the deep sea or ocean. They could hear through waves and communicate by responding to ultrasonic waves.
Option D is not the correct answer.

Hence, Option A is the correct answer.

Note:
Animals have lower intensity than human beings. Their sensory organ captures waves below twenty hertz. Animals which live in water like- dolphins, whales require high intensity as sound waves in water find it difficult to travel in water. Insects and bats, dogs beetles, toads, these animals communicate through ultrasonic sound waves. Ultrasonic sounds emit frequencies up-to twenty thousand hertz.