To fix the sentence, change "," after 2004 to ";" and remove the "and" before scientists. It makes the sentence sound better.
I hope that helps!
An independent clause is a sentence or part of one that can stand alone.
So I have a feeling that the first one is correct as "My sister and I love to cook" and "we spend hours cooking together" can both stand alone yet are joined by a semicolon.
I hope this has helped
The tomcats and the Huskies were the two teams that battled for the city championship
