AP BIOLOGY

Detailed explanation-1: -The antheridium mature to release antherozoids, which are biflagellate in structure. They swim in the water and fertilise with the egg of the archegonium. The formation of the diploid zygote leads to the second life phase of mosses, the sporophyte.

Detailed explanation-2: -Some successfully end up on female gametophyte moss plants and are chemically attracted to the archegonium. Each archegonium holds one egg, in a swollen section called the venter. The sperm enter the archegonium through the narrow channel in its neck. Fertilization occurs in the archegonium to form a diploid zygote.

Detailed explanation-3: -Answer and Explanation: Mosses need water for fertilization because they lack the pollen granules used by other types of plants to deliver sperm cells to ovules or the egg cells within the ovules.

Detailed explanation-4: -The fertilization process begins with the sperm of one moss reaching the egg. The sperm cell will then make its way toward the egg using water as a medium to find an opening called an ostium.

Detailed explanation-5: -Strangely enough, the moss gametophytes are now entirely dependent upon a rain shower for fertilization to take place. Water collects and is held at the top of the gametophytes by the paraphyses. The antheridia absorb this water and swell, releasing their sperm.