According to the Premack principle, which of the following statements are true about reinforcement through behavior sequences? Reinforcers are always stimuli, not behaviors. Reinforcement involves a sequence of two behaviors. High-probability behavior can reinforce a low-probability behavior. Reinforcement depends on the inherent appeal of the behavior. Low-probability behavior can reinforce a high-probability behavior. One behavior can serve as a reinforcer for another. Select one: 3, 5, 6 1, 4, 5 1, 2, 6 2, 3, 6