The answer is tree hope this helped :)
After a thorough research, I was able to found out the correct answer of the statements.
<span>Mosses that reproduce with gametes are___, and those that reproduce with spores are____
</span><span>Mosses that reproduce with gametes are "gametophytes", and those that reproduce with spores are "sporophytes."</span>
I do believe that it is both naturally occurring and caused by human activity. Although science has proven that it is something that naturally progresses with time, humans have sped up the process. Hope this helps:)