Question

When there are two haploid nuclei per cell in some fungi before forming the diploid structure, this stage is called
A. Diplotene
B. Diplophase
C. Haplophase
D. Dikaryon

Answer 1

Meiosis, also known as reduction division, is a process in which a germ cell divides into four gametes, or sex cells, each having half the number of chromosomes as the original cell. Meiosis is a process that occurs in sex cells, such as sperm and egg cells in the human body, to make more of them.
There are nine phases in the process of meiosis. Between the first time the cell divides (meiosis I) and the second time it divides (meiosis II), these are divided as follows:
Meiosis I - interphase, prophase $1$, metaphase $1$, anaphase $1$, telophase $1$ and cytokinesis.
Meiosis II – prophase $2$, metaphase $2$, anaphase $2$, telophase $2$ and cytokinesis.

Complete answer:
Option A: The paired homologous chromosomes begin to split and chiasmata become evident during this stage of meiotic prophase, which follows pachytene. Except at chiasmata, homologous chromosomal pairs begin to split and migrate apart from one another in the late stages of prophase I of meiosis I. Meiosis is a type of cell division that produces genetically different gametes or sex cells.
So, option A is not correct.
Option B: When an organism's chromosomes are diploid, it is at this stage in its life cycle.
So, option B is incorrect.
Option C: In the life cycle of certain plants, the haploid phase (as the gametophyte).
So, this option is not correct.
Option D: Fungi such as Ascomycota and Basidiomycota go through a reproductive phase called dikaryon, in which two genetically distinct nuclei coexist in a single cytoplasm before fusing.
So, option D is correct.

So, Option D is the correct answer.

Note:
When people say "cell division," they usually mean mitosis, the process of creating new body cells. The cell division process that leads to the creation of egg and sperm cells is known as meiosis. Mitosis is a necessary part of existence. There are three major types of cell division: binary fission, Mitosis, Meiosis
Cell division is used by all multicellular animals for growth, maintenance, and repair of cells and tissues. Cell division is the technique of reproduction for single-celled organisms. All human cells (excluding those that generate eggs and sperm) are somatic cells, which divide on a regular basis.