During meiosis, the diploid cell goes through a process of reduction division wherein 4 haploid cells are formed. Each haploid cell contains half the number of chromosomes in a diploid cell.

C. it halves

In Mendel’s experiment, the F2 generation resulted from a cross between two heterozygous parents. Let’s say for example that the genotype of each heterozygous parent is *Aa*.

Therefore, the phenotypic ratio that Mendel observed in his F2 generation was **3:1**. This means that 75% exhibit the dominant trait (*AA*, *Aa*) while 25% exhibit the recessive trait (*aa*).

A

In telophase II, 4 haploid cells are formed. Each haploid cell contains half the number of chromosomes in a diploid cell.

E. telophase II

C. incomplete dominance

A gene map is used to show the relative location and the distances between genes. By determining the recombination frequency of genes during crossovers, the relative distance between genes can be mapped.

D. recombination rate

In meiosis I, it starts with a diploid cell with a homologous chromosome pair. The crossing of genetic material between chromosome pairs also occurs in this stage. The alleles containing the same trait would get separated so a new combination of alleles can be produced.

B. meiosis I

Genes A, B, C, and D are separated by the following map units: C to D has 25 map units, A to B has 12 units, B to D has 20 map units, and A to C has 17 map units. According to this gene map, A to D has 8 map units.

B. 8

Genes A, B, C, and D are separated by the following map units:
a. C to D has 25 map units
b. A to B has 12 units
c. B to D has 20 map units
d. A to C has 17 map units
e. A to D has 8 map units

Only the gene map in choice D best reflects the map units given above.

D

The four principles of genetics that are proposed by Gregor Mendel includes the principle of dominance, the principle of segregation, the principle of biological inheritance, and the principle of independent assortment. Therefore, the crossing over that occurs during meiosis is not proposed by Mendel.

The chromosomal crossover during meiosis is discovered by Frans Alfons Janssens and it was described in theory by Thomas Hunt Morgan.

D. crossing-over occurs during meiosis

Crosses between parents with different traits would result in **hybrid** offspring. This is because different alleles are crossed together, thus resulting in heterozygous or hybrid progeny.

For instance, if one parent has a genotype of *AA* and the other has a genotype of *aa*, then crossing them together would yield offspring with a genotype of *Aa*. This is known as a hybrid.

B

A phenotype refers to the observable characteristics of an organism such as its physical appearance and behavior.

A. phenotype

A homozygous organism contains identical alleles, whether dominant or recessive, on both homologous chromosomes. If an organism is homozygous, it has identical alleles for a single trait.

D. homozygous