Which activity is associated with Freud's anal stage of development?

The activity associated with Freud's anal stage of development is the beginning of toilet training. This stage typically occurs between the ages of 18 months and 3 years and focuses on the child's control over bodily functions, particularly bowel control. During this stage, children learn to manage their bodily functions, which is a significant aspect of their developing autonomy and independence. Successful toilet training can lead to feelings of accomplishment and control, while struggles in this area may contribute to conflicts that can shape personality in later life, according to Freud's theory.

The other activities mentioned are linked to different stages of development. For example, the development of sexual identity aligns with the phallic stage, where children begin to explore their own bodies and the differences between genders. Exploring body differences also pertains to the phallic stage as children become more aware of their physical identity. The development of defense mechanisms is more relevant to later stages of psychological development where individuals learn to cope with emotional conflicts and stressors. Thus, the correct choice highlights the significant milestone of toilet training within Freud's framework for the anal stage of development.