The eukaryotic, multicellular, saprophytic organisms reproduce sexually by

Step-by-step solution

The eukaryotic, multicellular, saprophytic organisms are Fungi. Zygospores are formed by fusion of two gametes. It is seen in Phycomycetes. Sexual spores are called ascospores are produced endogenously in sac like asci in Ascomycetes. In Basidiomycetes, plasmogamy is brought about by fusion of two vegetative or somatic cells of different strains or genotypes. The resultant structure is dikaryotic which ultimately gives rise to basidium. Karyogamy and meiosis take place in the basidium producing four basidiospores.