Final answer:
Sympatric speciation requires conditions that lead to reproductive isolation without geographic separation, specifically disruptive selection and positive assortative mating. Stabilizing selection does not lead to speciation as it reduces genetic variance. The correct option would be 4) A and C are correct.
Step-by-step explanation:
Conditions Necessary for Sympatric Speciation
Speciation refers to the process by which new species are formed. One specific type is known as sympatric speciation, which occurs without geographic separation. The necessary conditions for sympatric speciation include:
Disruptive selection: This occurs when extreme values for a trait are favored over intermediate values, thereby differing from stabilizing selection that favors average values and leads to decreased genetic variance.
Positive assortative mating: This is when individuals are more likely to mate with others that are similar to themselves in certain characteristics.
Both of these conditions can lead to reproductive isolation even when populations live in the same geographic area. Stabilizing selection, on the other hand, would not typically lead to sympatric speciation because it reduces genetic variance and does not lead to isolation.
Therefore, the conditions thought to be necessary for sympatric speciation to occur are:
Disruptive selection
Positive assortative mating
Answering the student's question, the correct option would be 4) A and C are correct.