Final answer:
Mardi Gras is a 40-day season of fasting and reflection observed by the Catholic Church from Mardi Gras Day to Easter Sunday. It involves fasting and abstaining from meat as a form of spiritual discipline. The Gregorian Calendar reform was implemented to prevent Easter from occurring in the wrong season.
Step-by-step explanation:
Mardi Gras marks the beginning of a 40-day season of fasting and reflection that lasts until Easter Sunday. This tradition began with the Catholic Church and is observed by members of the Latin Catholic Church. During this time, fasting and abstinence from meat are practiced as a form of spiritual discipline and preparation for the celebration of Easter. The Gregorian Calendar reform in 1582 was undertaken to ensure that Easter would not be celebrated in the wrong season.