Final answer:
The correct statement about fungi is karyogamy, which refers to the fusion of two haploid nuclei to form a diploid zygote.
Step-by-step explanation:
Statement A) Fungi are commonly identified using biochemical tests. This statement is not true. Fungi are typically identified using morphological characteristics such as spore structure and type.
Statement B) Most fungi reproduce only asexually. This statement is not true. Fungi can reproduce both sexually and asexually, depending on the species.
Statement C) Karyogamy refers to a part of the sexual reproduction cycle in which two haploid nuclei fuse to form a diploid zygote. This statement is true. Karyogamy is the fusion of two haploid nuclei to form a diploid zygote.
Statement D) Conidiospores are spores that are enclosed in a specialized sac-like structure. This statement is not true. Conidiospores are spores that are produced externally and are not enclosed in a specialized structure.
In summary, statement C) is the correct statement about fungi.