Final answer:
The sentence 'Comen todas estas postres' is grammatically incorrect. It should be 'Comen todos estos postres' (They eat all these desserts).
Step-by-step explanation:
The sentence 'Comen todas estas postres' is grammatically incorrect. In Spanish, nouns and adjectives must agree in gender and number. The word 'postres' is a plural noun, but the adjective 'estas' is feminine and singular. To make the sentence grammatically correct, it should be 'Comen todos estos postres' (They eat all these desserts).
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