How bat use ultrasound to detect prey and how the ultrsound is only deflcted from a prey it can also deflected from a tree n so how bat doesnt confuse?

Dear Student

Bats emit ultrasonic waves from their mouth (squeaks ). When these touch the prey, the waves get reflected back to the bat. The bat detects these waves and his brain estimates the distance and direction of the prey by the time taken, the loudness of the sound and the direction of the sound.

Bats send out a series of high-frequency calls that bounce off nearby objects including their prey. By listening to the echoes, the bats are able to build up an auditory image of their environment and thus pinpoint the location of their prey. These returning echoes give the bats information about everything that is ahead of them (including the size and shape of the object). 
This system of finding prey is called echolocation.

So they can distinguish between their prey and other objects in the surroundings
Regards