Question

a unique discovery made on the island of surtsey shortly after its formation was that ____. some landforms appeared ancient the entire island appeared young, as expected pottery was found below the surface flows the island was a seamount

Explanation:

Surtsey is a volcanic island formed in 1963 - 1967. Finding pottery below surface flows is unique as it implies human - related artifacts in a newly formed natural environment. Ancient - appearing landforms or the island being a seamount are not unique discoveries after its formation. And it being young is expected for a newly formed island.

Answer:

pottery was found below the surface flows