Final answer:
The painting 'The First Thanksgiving 1621' by J.L.G. Ferris belongs to the artistic style of realism, which aims to depict subjects realistically and objectively.
Step-by-step explanation:
The painting 'The First Thanksgiving 1621' by J.L.G. Ferris falls under the artistic style of realism. Realism is an artistic movement that emerged in the 19th century and aimed to depict subjects realistically and objectively, often portraying ordinary people or events in a lifelike manner. The artist's depiction of the First Thanksgiving captures the scene in a realistic manner, showcasing the characters and the event as they would have occurred.