Question

recovering artifacts from shipwrecks on october 5, 1804, the spanish ship nuestra señora de las mercedes sank following an attack from a british naval ship. the mercedes fell to her underwater grave carrying more than 17 tons of gold and silver coins. more than two hundred years later, in 2007, a treasure - seeking group discovered the mercedes wreck and retrieved the coins from the bottom of the ocean. the discovery is considered one of the largest treasures ever found. which evidence supports the authors claim that finding treasure can be a great challenge? government officials work with archaeologists to study shipwreck remains. some items are covered in a thick patina that covers important details. electrolysis can cause a chemical reaction that damages coins. researchers use robots and other machines to help recover delicate artifacts.

Explanation:

To support the claim that finding treasure is a great challenge, we need evidence of obstacles in the process.

• The first option describes collaborative work, not a challenge.
• The second option notes that a thick patina hides important details, which creates difficulty in identifying or working with the artifacts, a clear challenge.
• The third option refers to a risk in preservation after recovery, not the act of finding the treasure.
• The fourth option mentions tools that assist recovery, not a challenge.

Answer:

Some items are covered in a thick patina that covers important details.