the sentence that contains the main idea is that "chocolate has been found to be a cause of weight gain."
the paragraph is pointing out the fact that it has been <em>found </em>to cause weight gain but the paragraph goes on to say that some of the researchers don't dive deep enough.
i hope that was helpful :D
Explanation:
A comma should follow a dependent clause when the dependent clause comes first in a sentence. A dependent clause is the clause which cannot stand alone in its meaning on the other hand independent clause refers to the phrase which can stand alone, though both have a subject and a verb.
Odysseus. Athena is scolding Odysseus for questioning whether the avengers can be put off. Odysseus is scolding Telemachus for questioning Athena's help. Odysseus is justifying his purifying the house with smoke.
