Final answer:
Among the movie options for a mixed media assignment, 'Elf' stands out as the most popular based on its cultural impact and status as a holiday classic, although 'Finding Dory' also saw considerable success, especially with families.
Step-by-step explanation:
In choosing a popular movie option for a mixed media movie appreciation assignment regarding films from the 2000s, the question presents three options: Finding Dory, Elf, and Cloudy with a Chance of Meatballs. Considering box-office success, critical reception, and cultural impact, Elf, starring Will Ferrell, is often cited as a holiday classic and has had a significant impact on pop culture. Its longstanding popularity, especially during the holiday season, likely makes it the most popular among the options listed.
On the other hand, Finding Dory, the sequel to the acclaimed Finding Nemo, also achieved considerable box-office success and popularity, particularly with family audiences. It is important to note that while Cloudy with a Chance of Meatballs was well-received and successful, it may not have the same level of cultural impact as the other two.