Final answer:
The most frequently preferred Native American/First Nation term for people who blend the masculine and feminine is two-spirit people.
Step-by-step explanation:
According to the information provided, the most frequently preferred Native American/First Nation term for people who blend the masculine and feminine is two-spirit people. This term was coined by Native American LGBTQ people in 1990 to resurrect their heritage of variant gender. It represents individuals who have both male and female spirits.