Answer:
<em>The Cliff Palace should have been protected and preserved.</em>
Zweiundzwanzig is your answer .-.
"I" would be the correct wording for the sentence.
A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mechanism.
I feel that Korean is a good language to learn, though the reason to learn it may not be due to the K-pop and dramas. Korean has other values, and also has many interesting aspects, but some of those extra things may not be the only reason to learn it.
Overall, if you have the time it's a cool language to learn.