In looking at the organizational structure of the Tupamaros, the Executive Committee was in charge, but it ran a highly decentralized operation. Its main power came from the internal rule enforcement provided by the Committee for Revolutionary Justice. Columns were the major units, but they tended to be tactical formations. The real operational power came from the cells, which joined for column-style operations on rare occasions. The combat striking power of the Tupamaros came from the four- to six-person groups in the cells. Which term best describes the organizational structure of the Tupamaros