Final answer:
The Mexican army took back the cannon they had given the colonists for protection due to their perceived threat to control and the challenge posed by the colonists' rebellion and the establishment of the California Republic.
Step-by-step explanation:
The Mexican army decided to take back the cannon they had given the colonists for protection because they saw the colonists as a threat to their control. The Mexican army took back the cannon they had given the colonists for protection due to their perceived threat to control and the challenge posed by the colonists' rebellion and the establishment of the California Republic.
The colonists had rebelled and declared a new government, the California Republic, which the Mexican army saw as a direct challenge to their authority. By reclaiming the cannon, the Mexican army aimed to weaken the colonists' ability to resist and maintain control over the territory.