Thanks for the question! So I’m assuming your’e asking about the second sentence, which has two most statements in it. First, we’re told that most North American mammal species aren’t rodent species. So this is
North American mammal species —most—> ~Rodent species
Then, we’re told that most of the individual mammals in North America are rodents. So this is
Individual mammals in North America —most—> Rodents
Now we can’t really use these statements for this particular question, since it involves thinking about the relationship between the species and the population of its members, but that’s how you would diagram them.
Hope this helps! Feel free to ask any other questions that you might have.