Final answer:
Liverworts in the gametophyte stage have leaflike, stem-like, and root-like structures. The Marchantia liverwort has a complex thalloid structure with a flattened body that differentiates into a top and bottom. The gametophyte produces antheridiophores and archegoniophores for sperm and egg production.
Step-by-step explanation:
In liverworts, the gametophyte stage is the dominant and most visible stage. It has leaflike, stem-like, and root-like structures. For example, in the liverwort Marchantia, the gametophyte is a complex thalloid structure, consisting of a flattened body (thallus) that spreads across the ground and is differentiated into a top and bottom. The top layer has open pores to allow for carbon dioxide entry, while the bottom layer has structures that attach the liverwort to the substrate. The gametophyte produces umbrella-shaped structures called antheridiophores and archegoniophores, which produce sperm and eggs respectively.