Selena often works late into the night, and Bernardino also often works late.
1. The adverb that modifies the verb is c) ever. Without it, it wouldn't be completely clear as to which time frame the speaker refers to. It may have been for example the last year, or in some other particular moment.
2. The adverb that modifies the verb is b) always. It adds to the sense of urgency of wearing a life jacket when rafting. Without it, the meaning of this sentence wouldn't be so precise.
The heat becuase thats what they are talking about
Sentence two is correct for sure, and I think the last one is correct also, I'm not 100% sure though for the last one.
I believe it is a coordinating conjunction. I’m not sure but I hope this helped.