Here's why:
* Simile: A simile is a figure of speech that compares two things using the words "like" or "as".
* Comparison: The sentence compares the beads of sweat to raindrops.
* "Like" Keyword: The sentence uses the word "like" to make the comparison.
Therefore, "Tiny beads of sweat like raindrops dripped off his arms" is a simile.