Suggest improvements for the highlighted problem area:
In the debate about the source of the Mississippi, we heard three student's opinions:
Nathan: It isnt any mystery that the source of the Mississippi is the northeast corner of Minnesota. In 1832, Henry Schoolcraft proved that the river began with springs under Lake Itasca.
Hillary: Nathan, your wrong. Actually, the Missouri River is longer than the upper Mississippi and has a larger area from which it collects water. Therefore, the true source of the Mississippi is the Rocky Mountain region of western Montana.
Cecil: Hillary and Nathan's ideas fail to recognize the big picture. The waters of the Mississippi come from rain clouds that float over 22 states and 2 provinces in North America.
- Apostrophe for Ownership -
Also in the opening paragraph, we have a need to show ownership by several nouns:
Hillary and Nathan's ideas fail to recognize the big picture.
The sentence obviously refers to both the ideas that belong to Nathan and the ideas that belong to Hillary. To show this individual ownership by two or more nouns, make each noun possessive:
Hillary's and Nathan's ideas fail to recognize the big picture.
Note that only one apostrophe, after the final noun, is needed when we want to indicate joint ownership:
Hillary and Cecil's teacher was proud of their creative thinking about the Mississippi and its source.