Frequency more than 20,000 HZ​

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Explanation:

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The units of frequency are called hertz (Hz). Humans with normal hearing can hear sounds between 20 Hz and 20,000 Hz. Frequencies above 20,000 Hz are known as ultrasound

The correct answer is 2) Election of Abraham Lincoln.

The election of Abe Lincoln in 1860 resulted in the secession of several different US states. The first state was South Carolina, who seceded from the Union just one month after Lincoln was elected. In January, just two months after secession, Mississippi, Florida, Alabama, and Georgia all seceded within a few days of each other. This would ultimately lead to the beginning of the Civil War.