Answer:
The groups formed are: Jack's group and Ralph's group.
Step-by-step explanation:
"Lord of the Flies" tells the story of a group of boys who are being pulled out of England to escape a war. They are being taken to a safe place and during the trip, the plane, where the boys were, suffers an accident and crashes on a desert island. All boys survive, but adults die.
The boys stay on the island, without adult supervision.
One of the boys is called Ralph and establishes himself as a leader, building shelters and keeping a sign of fire always on. For Ralph it is important that the boys stay organized and civilized until a rescue arrives. The younger boys obey what Ralph says and form a group with him.
However, the bigger boys form a group with Jack and organize themselves in a way completely contrary to the other group. Jack's group indulges in savagery and decides to live completely outside social and organizational standards, indulging in violence and a lack of rules.