Complete the following sentence :
Bats can produce and hear ............ sound.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks us to complete the sentence about the type of sound that bats can produce and hear.

2. **Identifying the Characteristics of Bat Sounds**: Bats are known for their unique ability to navigate and hunt using sound. They produce sounds that are beyond the range of human hearing.

3. **Defining the Range of Human Hearing**: The human ear can typically hear sounds in the frequency range of 20 Hz to 20 kHz (20,000 Hz). Sounds above this frequency are not audible to humans.

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