Final answer:
The sentence that uses the word 'ramifications' correctly is sentence c.
Step-by-step explanation:
The sentence that uses the word 'ramifications' correctly is sentence c. 'Their numbers will decline as their plant hosts of butterflies may not flower earlier and young amphibians may not be viable as there might be a lack of water.' The word 'ramifications' refers to the possible negative consequences or effects of an action, and in this sentence, it accurately describes the potential outcomes of a lack of water for these species.