The 1898 Paris Treaty which ended the Spanish-American War.
The US Constitution.
Houses in Puerto Rico are Commonly made of cement
Puerto Rico is a US Territory and has not achieved statehood.
The mutation of the "o" in the Latin roots to the "ue" in modern Spanish was something that developed after the first colonization of Puerto Rico took place. As a result, the first name of Puerto Rico was Porto Rico. (This was very quickly replaced by the Puerto Rico.)
Paper or cardboard.
Puerto Rico is currently a territorial possession of the United States. Even though a territory of the United States, YES, Puerto Rico is considered an island nation. Since they are "part, but NOT part" of the United States. Over many years, despite the island's status, Puerto Rico and Puerto Ricans have build up their own identity and a strong nationality now seen and felt around the world. The mojority of Puerto Ricans, even with US citizenship, say that they are Puerto Rican, not american, and that Puerto Rico is their country, not the United States. Despite debates and politics, you can say Puerto Rico is considered a different nation. (Own national anthem, own national flag, own national olympic team, own Miss Puerto Rico, and other national identities that have made Puerto Rico its own nation) (Not a soverign nation though)
Rainforest.
No, it was made by volcano thousands of years ago.
It is believed to have been created in 1892.
Pina Colada.
The Spanish-American War.
None so far.