【答】where the Mediterranean now connects to the Atlantic是非限制性定语从句，修饰the Strait of Gibraltar。句子成分划分如下：

As a result of crustal adjustments and faulting（原因状语）, the Strait of Gibraltar（主语）, where the Mediterranean now connects to the Atlantic（定语从句）, opened（谓语）, and water cascaded spectacularly back into the Mediterranean（与前句是并列分句，不再细分了）.

（直布罗陀海峡）