Final answer:
In ferns, mosses, and similar plants, two generations are required to complete the reproductive cycle.
Step-by-step explanation:
In ferns, mosses, and similar plants, the reproductive cycle requires two generations to complete. This is known as alternation of generations. The dominant generation in these plants is the sporophyte stage, which is the green, photosynthetic structure that we recognize as a fern. The other generation, the gametophyte stage, is usually smaller and less noticeable.