Question

state the use of echo by a bat,dolphin and fisherman

Answer 1

they use echo to prey on their food and also find the way during travel

Answer 2

bat:
Echolocation is the use of sound waves and echoes to determine where objects are in space. Bats useecholocation to navigate and find food in the dark. To echolocate, bats send out sound waves from their mouth or nose. When the sound waves hit an object they produceechoes.
dolphin:
Dolphins have developed the ability touse echolocation, often known as sonar, to help them see better underwater. Scientists believe this ability probably evolved slowly over time. Echolocation allows dolphins to “see" by interpreting the echoes of sound waves that bounce off of objects near them in the water.
fisherman:
Echo sounding is a type of sonar used to determine the depth of water by transmitting sound pulses into water. ... Echo sounding can also refer to hydroacoustic "echo sounders" defined as active sound in water (sonar) used to study fish.