Adverbs in He looked down and saw a highly unusual stone

The adverbs in the sentence are down and highly.

Explanation:

Down- this is modifying the word look.It shows where she looked.

Highly- this modifies the adjective unusual.The stone was not just unusual,the word highly there shows that it was to a higher level.

I hope this helps :)

- "about the claims : -

making a claim is just a fancy way of saying that you're stating your main point.' claims are not just opinions. a claim tells what you think is true about a topic based on your knowledge .

about the country claims : -

a counterclaim is just the opposite of a claim. counterclaims are also provable and supportable by reasons and evidence. not just, 'because i said so.' when you're planning an argument, you need to know what the counterclaim might be so that you can make sure that you disprove it with your reasons and evidence your research." - (catherineroberts)

do your own work !