Question about the question in Erica Meltzer's grammar book

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1

Healthy arctic marine mammals have a thick layer of fat beneath the skin. Tropical marine mammals have very few fat reserves in their bodies.

“skin. Tropical marine mammals” is underlined

The question is “what is the best way to join these sentences”, and the answer is : … beneath the skin, whereas tropical…

Why is it grammatically correct? “Whereas” isn’t a FANBOY word, so we need to put a semicolon before it, don’t we?

2

No–the semicolon is for conjunctive adverbs, but whereas is a subordinating conjunction, thus rendering the clause after the comma a dependent clause, and of course IC,DC is a fine construction. Clear explanation: http://speakspeak.com/resources/english-grammar-rules/conjunctions/whereas @SaintPetersburg

3

Thank you so much!