산 중에 제일 높은 산은 백두산이고 가장 아름다운 산은 금강산입니다. The "이고" works as usual?

Question

이고

Each noun are connected as the same level by it.

For example.

부장이고 사장이고 ...　The leader and the boss , all is ...

옷이고 신이고 ... The clothes and the shoes , all is ...

But...

산 중에 제일 높은 산은 백두산이고 가장 아름다운 산은 금강산입니다.

It is little weird to me. It seems that this sentence is different a little.

I can understand if this sentence is as follows:

백두산 이고 금강산 이고 조선의 산 입니다.

But the subject sentence has two nouns and they are written separately.

Nonetheless, 이고 is used...

why?

Answer 1

이고 in your sentence just means 'and'.

Translated: Among mountains, the highest mountain is 백두산, and the most beautiful mountain is 금강산.

The 이고 in the sentence comes from 이다 (to be) + ~고 (and, grammar point to make and-form of a verb), so 이고 is used to state two different things on each side of the 이고, just like the English 'and'.