Final answer:
The error in the sentence 'Today Jeremy ate two whole pizzas, and he is the president of our class.' is related to logical construction. The two pieces of information given do not appear to be logically connected which can confuse the reader.
Step-by-step explanation:
From the sentence provided, it appears there are no issues related to subordination, parallelism, dangling modifiers, misplaced modifiers, or sentence fragments that make it grammatically incorrect. However, it seems there could be an issue with logical construction.
Offering two pieces of non-related information (Jeremy eating two whole pizzas and being president of the class) in one compound sentence may confuse the reader as to whether there is a logical correlation between the two facts, when there is likely not.
To correct this, you might separate the two ideas into individual sentences or clarify their relevance if they are indeed related.