[1] Echolocation is used by bats to navigate and find their prey. [2] Echolocation is a process of locating objects by hearing how sound echoes off them. [3] Vibrations in the larynx, a part of the bat's throat, make high­-pitched sounds. [4] When these vibrations occur, the sound escapes through the bat's nose or mouth. [5] Bats can produce sounds so high that humans cannot hear them.

Question

[6] The bat's ears are adapted to hearing these high­-pitched sounds. [7] Because these sounds can be damaging to the inner ear, a muscle in the bat's middle ear contracts before the bat makes a high­-pitched sound. [8] This reduces the ear's sensitivity to sound. [9] By the time the sound echoes, the middle ear muscle has relaxed, allowing the bat to hear its high­-pitched echo.

[10] Echolocation helps bats avoid running into things. [11] Sounds are made by the bat that will bounce off any obstecle in the bat's path. [12] When the sound returns to the bat, the bat can approximate the location of these objects. [13] The bat will then amend its flight pattern to avoid crashing into anything while in flight. [14] Echolocation is especially useful for bats because they do not see well in the dark. [15] If a bat were blindfolded, it could still fly safely because of echolocation.

[16] Bats also use echolocation to catch their prey. [17] If prey is in motion, the bat can follow it using echolocation. [18] By listening to the echoed sounds, a bat can determine its prey's speed, altitude, and size. [19] These high-pitched noises are repeated by the bat at a faster rate as it nears its target. [20] Repeating the sound helps improve the bat's accuracy in pinpointing its prey's location. [21] Without using echolocation it would be difficult for bats to catch their preyWhich of these best revises Sentence 19 to add clarity to the passage?
Answer choices for the above question

The bat repeats these high-pitched noises at a faster rate as it nears its target.

As the target is neared, the bat repeats these high-pitched noises at a faster rate.

As it nears its target, these high-pitched noises are repeated by the bat at a faster rate.

These high-pitched noises are repeated by the bat at a faster rate as the target is neared.

Answer 1

The best revision for Sentence 19 to add clarity to the passage is:

The bat repeats these high-pitched noises at a faster rate as it nears its target.

This option clearly indicates the subject (the bat) and the action (repeats the noises) in a straightforward and active voice, enhancing the clarity of the sentence.