Question

1. There were big, medium, and small dinosaurs. Some ate plants, others ate meat, some ate both meat and plants, the rest ate fish.

2. 1. There were big, medium, and small dinosaurs. Some ate plants, some ate meat, some ate both meat and plants, the others ate fish.

3. There were big, medium, and small dinosaurs. Some ate plants, others ate meat, others ate both meat and plants, the rest ate fish.

(Are the example passages grammatical?)

Answer 1

All three are worded fine, but the punctuation in the second sentence in each set needs fixing.

In the first sentence in each set, your use of commas is correct since the series is made up of nouns. Commas would also be correct if the series were made up of phrases.

In the second sentence in each set, all commas need to be changed into semicolons (;) since the series is made up of clauses.

Phrase = 2 or more words that go together in the sentence and are not clauses.

Clause = a group of words that go together and include a subject and verb.

Do you see the difference?