Answer:
Gametophyte
Step-by-step explanation:
Plants as well as other living organisms, during their reproductive life cycle, exhibit a switch between haploid state and diploid state. This process is referred to as ALTERNATION OF GENERATION. Plants are diploid organisms i.e. most of their cells contain two sets of chromosomes. This diploid state of their life cycle is called SPOROPHYTIC stage.
During reproduction, the diploid sporophyte of the plant undergoes meiosis i.e. reduction division to produce haploid spores. These haploid spores germinates and undergoes series of mitotic divisions to form the haploid GAMETOPHYTE of the plant, which is the haploid form of the plant. The gametophye of the plant produces haploid gametes (sperm and egg) which combines in a process called FERTILIZATION to produce a diploid ZYGOTE that grows via mitosis into the diploid SPOROPHYTIC structure of the plant.
The cycle starts again from the beginning, hence, it is called an ALTERNATION OF GENERATIONS.