Prophase I is the correct answer. During oogenesis in mammals, meiosis I occurs during the prenatal age. When the germ cells reach prophase I, the cell cycle is arrested, and the cells are frozen in prophase until puberty.

During puberty, the female will begin to ovulate. This means that one egg cell will progress from prophase I to metaphase I and complete meiosis on a cyclical basis, known as the menstrual cycle.

Meiosis allows for the creation of genetically different haploid cells from one original germ cell. Following anaphase I, homologous chromosomes are separated from one another, resulting in a halving of the genetic material (haploid). As a result, the two cells are haploid following meiosis I. The separation of genetic material in anaphase II involves the splitting of chromatids, not homologous chromosomes. This does not affect the number of chromosomes in each cell, meaning all cells remain haploid.

Parent: diploid (XX)

Meiosis I: haploid, full chromosome (X)(X)

Meiosis II: haploid, single chromatid (/)(\)(/)(\)

Note that crossing over can only occur when the cell is diploid in meiosis I, specifically during prophase I.

The processes of mitosis and meiosis have many characteristics in common (i.e. cytokinesis, chromosome condensation, and nuclear membrane reformation); however, there are key differences that distinguish the processes from one another. One of these differences is the cell type that result from each respective process. Mitosis results in two daughter cells with the same number of chromosomes as the parent cell. Meiosis, on the other hand, yields four daughter cells with half of the number of chromosomes as the parent cell—“haploid” cells.

In most vertebrates, sperm cells join with egg cells to form a zygote. Each cell produces a haploid complement of chromosomes in order to form the zygote. The result is a new organism with a full set of maternal chromosomes and a full set of paternal chromosomes.

When a sperm joins with an egg, only the nucleus of the sperm enters to egg to form the zygote. The nuclear envelope is then altered, allowing the paternal DNA to intermix with the maternal DNA in the zygote nucleus. The sperm does not contribute a nucleus (only genetic material), cytoplasm, or diploid copies of any chromosome.

Crossing over occurs during prophase of meiosis I (prophase I). This process requires tetrad formation, where the homologous chromosomes (with their sister chromatids) pair with each other. Following tetrad formation, the genetic material from one homologous chromosome can be exchanged with that of the other. This exchange of genetic material leads to genetic recombination and results in production of non-identical gametes. Crossing over occurs only between homologous chromosomes. Sister chromatids are situated to form a single chromosome; crossing over does not include recombination of genetic material within a single chromosome.

Remember that crossing over is not a mutation and is a completely natural process for every sexually reproducing organism.

The processes of mitosis and meiosis have many differences between them. These differences include the genetic recombination event called crossing over unique to meiosis, the fact that only mitotic daughter cells are genetically identical to parent cells, and the paring of homologous chromosome pairs during metaphase I of meiosis. One characteristic that is common to both processes is that they occur in all animals.

For this question you have to carefully track the chromosomes through meiosis. A human cell in metaphase I will have formed the tetrads and would have aligned the genetic material along the metaphase plate. The sister chromatids are still attached to one another, so they only count as one chromosome per pair of chromatids. There are a total of 46 chromosomes in metaphase I, each comprised of two sister chromatids. There are 23 homologous pairs, each containing two complete chromosomes.

During telophase II, the cell is in a haploid state. The homologous pairs have been separated during anaphase I, such that each cell contains 23 complete chromosomes. Each chromosome is then broken into its chromatids, such that the total number of chromosomes represented during anaphase II is 46, with each chromatid representing a chromosome. If each of the chromosomes still had its sister chromatid, then the total number of chromosomes would be 23. Telophase II follows anaphase II. The 46 chromatids are sequestered to opposite sides of the cell, but the cell has not yet divided. A cell in telophase II is haploid, containing only one copy of each homologous chromosome, but contains two chromatids for each copy. The total number of chromosomes in a telophase II cell is thus 46. As soon as the cell completes cytokinesis, and two daughter cells are formed, they become haploid cells with 23 chromosomes each.

Remember that the law of independent assortment states that genes on different chromosomes are passed independently of one another to offspring. This phenomenon results from the random alignment of the chromosomes along the metaphase plate. This random alignment allows genes to be segregated independently, and occurs during metaphase I.

Metaphase II involves the alignment of single chromosomes along the metaphase plate for segregation of identical sister chromatids. Remember that independent assortment is only valid for genes on different chromosomes. Genes on the same chromosomes are not passed independently of one another from parent to offspring.

Independent assortment can, thus, only occur during metaphase I, since this phase involves alignment of independent, non-identical chromosomes.

For this question, remember that a cell containing only one homologue is a haploid cell. Cells containing two homologous chromosomes are considered diploid.

Following the S phase and mitosis, the cells are diploid because they contain pairs of homologous chromosomes.

Following meiosis I, however, the daughter cells are haploid because they contain only one homologue. These homologues still consist of two identical sister chromatids, which will be separated following meiosis II, but the halving of genetic material during meiosis I still generates haploid daughter cells.

Meiosis I involves the separation of homologous chromosomes, while meiosis II involves the separation of sister chromatids. The G2 phase precedes meiosis I or mitosis, but does no precede meiosis II. Interkinesis is the period that separates meiosis I and meiosis II.

Meiosis I results in two daughter cells, each with only one copy of each chromosome, from a parent cell with two copies of each chromosome. The parent cell is diploid, while the daughter cells are haploid. This is known as reductional division because the daughter cell contain less genetic material than the parent cell. Meiosis II results in four daughter cells from two parent cells. Each parent contains one copy of each chromosome, and each daughter cell also contains one copy of each chromosome (although the material is stored on a single chromatid). Since both parent and daughter cells contain the same amount of genetic information, this is considered an equational division. The daughter cells of both meiosis I and meiosis II contain only one copy of each chromosome, as homologous pairs have been separated. Both meiosis products are thus considered haploid, making this the correct answer.