Mosses are non-vascular plants, which means they lack the specialized tissues (xylem and phloem) that transport water and nutrients. Because of this, they are considered to be part of the bryophyte group, which is thought to be the oldest lineage of land plants (though not the most ancestral).

Therefore, it's not accurate to say a specific generation is "dominant" in mosses. Both the gametophyte (haploid, produces gametes) and sporophyte (diploid, produces spores) generations are present in the moss life cycle, but the gametophyte is the dominant stage. This means the gametophyte is the larger, more independent, and longer-lived stage.

Here's why the gametophyte is dominant:

* Independent: The gametophyte is photosynthetic and can produce its own food.

* Larger: The gametophyte is the leafy, green structure we typically recognize as moss.

* Long-lived: The gametophyte can live for many years, while the sporophyte is relatively short-lived and dependent on the gametophyte for nutrition.

In contrast, the sporophyte in mosses is smaller and more dependent on the gametophyte for support and nutrition. It is typically a stalk with a capsule at the top, where spores are produced.

So, while both generations are present in the moss life cycle, the gametophyte is the dominant generation.