The correct answer is option 2, which includes sexual reproduction, asexual reproduction, and mutations as causes of variation in the genetic material of progeny.
1. Sexual reproduction: This is a process where genetic material from two parents combines to create offspring with a unique combination of genes. This leads to variation in the genetic material of progeny.
2. Asexual reproduction: In asexual reproduction, offspring are produced from a single parent without the involvement of genetic material from another individual. While asexual reproduction does not involve genetic recombination, there can still be variations due to mutations.
3. Mutations: Mutations are changes in the DNA sequence that can occur spontaneously or as a result of exposure to external factors like radiation or chemicals. Mutations introduce variations in the genetic material of progeny, as they can lead to changes in gene sequences or gene regulation.
4. Epigenetic changes: Epigenetic changes refer to modifications to the DNA that do not involve changes to the DNA sequence itself. While these changes can affect gene expression and phenotype, they do not directly cause variation in the genetic material of progeny.
Therefore, options 1, 3, and 4 do not include all the correct causes of variation, making option 2 the correct answer.