Sure, these two words are quite similar in nature but the distinction lies in the context of speech.
1. Prevalent means that there is a large or widespread 'presence' of something, for example you can say:
"Japanese cars are more 'prevalent' in America than in China."
2. Prevail means that something will take over another thing in terms of quantity, force, or willpower. for example, you can say:
"Although there is a lot of bad things happening in the world today, I believe goodness will 'prevail".
Hope this helps,