AP BIOLOGY

Detailed explanation-1: -In mosses, the dominant stage is the haploid generation (the gametophyte). This means that the green, leafy gametophytic tissue is haploid (has only one set of chromosomes). The gametophyte refers to all organs and tissues that are a part of the haploid generation.

Detailed explanation-2: -Mosses have leafy gametophytes. The leafy gametophyte of mosses has a variable number of rows of leaves on the upright axes. The gametophyte is anchored to the substratum through rhizoids. Mosses have multicellular and branched rhizoids.

Detailed explanation-3: -The second stage, a leafy stage, is produced by secondary protonema. To protonema, the leafy stage resembles a lateral bud. The spiral pattern of leaves is visible during the leafy stage. In mosses, secondary protonema evolves into the leafy stage.

Detailed explanation-4: -In mosses, as in liverworts and hornworts, the leafy shoots belong to the gametophytic phase and produce sex organs when they mature. The leafy shoots (often called gametophores, because they bear the sex organs) arise from a preliminary phase called the protonema, the direct product of spore germination.

Detailed explanation-5: -Mosses are simple in structure, tiny and leafy arrangements found around the thallus exhibiting radial or spiral symmetry. Liverworts, on the other hand, have foliose and thallus which are green-leaf like arrangements attached to the stem.