north american history according to middle schoolers

In my grade 7 World Geography class, we are just finishing our unit on Canada and the United States (Mexico gets lumped into the "Latin America" unit).

This morning over breakfast I marked my students' unit tests. I had to laugh at some of the answers given.

• "Before the Europeans arrived in North America, native life was pretty much built on nature and wildlife. They made clothing out of animal skins and used bones or elephant tusks to make weapons." 
• (Earlier in the unit, when presenting an immigration ad for Alaska, a student said, "All tribes are welcome in Alaska!" You can tell you're teaching in Africa when... students refer to elephants and tribalism!) 
• "Canada helped aid the US while the US fought in France to win the Cold War." 
• "Difference between Canada and the States: Canada has a smaller population. This is because Americans made lots of posters to attract many people." 
• "Similarity/Difference: Canada has less people than America. Fact: Almost or about less than 1 million. Similarity/Difference: More people in America. Fact: Over 1 million people." 
• And one poor girl's chart on similarities and differences in America vs. Canada: 
• "Canada continued in the slave trade. The US stopped slaved wanted Canada to stop to. Fact: Caused World War I." 
• "Canada wanted to get independence. The US never wanted Canada to get independence. Fact: Caused World War I." 
• "Population in Canada was less due to slaves running away. Fact: Less workers. Population in the US grew due to the slaves coming to their free country. Fact: High taxes."

Huh? 

I smile, shake my head, but if I think about it too long it gets a little depressing. Is this really how their brains are filtering what I'm saying at the front of the room? Thankfully, despite these funny errors, almost all the kids did really well on the test. I must have done something right .... right?