Final answer:
The model of relationship development that can be described as occurring in ten stair steps (or a staircase) is called the stages of family life or the family life course.
Step-by-step explanation:
The model of relationship development that can be described as occurring in ten stair steps (or a staircase) is called the stages of family life or the family life course.
These models recognize that families go through predictable phases or stages, but they also acknowledge that family development is fluid and can vary based on factors like gender, ethnicity, culture, and lifestyle.
Instead of rigidly following a linear progression, these models view family life as a course with different events and transitions, allowing for individual differences and changes in family dynamics.