Final answer:
Both sympatric and allopatric speciation can involve habitat differentiation, sexual selection, and polyploidy; however, geographic separation is unique to allopatric speciation since it requires physical distance to hinder gene flow. So the correct options are a, d, and e.
Step-by-step explanation:
The factors that can be involved in both sympatric and allopatric speciation include habitat differentiation, sexual selection, and polyploidy. Geographic separation is exclusive to allopatric speciation, as it involves physical distancing which interrupts gene flow between populations, leading to the formation of new species. In contrast, sympatric speciation occurs without geographic separation, often through mechanisms like polyploidy, where organisms have more than two sets of chromosomes, which can occur within a shared habitat.
Habitat differentiation can drive speciation in both scenarios by leading to distinct microenvironments within a shared space or by accentuating the divide caused by geographic barriers. Similarly, sexual selection can occur within the same geographic area or among isolated populations, where preferences in mate choice can lead to reproductive isolation and eventually to speciation.