"Mechanical" would be the kind of reproductive isolation among the choices given in the question that has been observed in these two species. The correct option among all the options that are given in the question is the first option or option "A". I hope that the answer has come to your help.
Mechanical reproductive isolation is a type of reproductive isolation in which morphological changes prevent successful mating or pollination.
Difference in structure or complementary nature of genitalia prevent the successful mating.
In plants, difference in structure of flower prevents the successful pollination.
In addition, plants achieve mechanical reproductive isolation by attracting different type of pollinators due to which pollination does not occur between different species.
The difference between granites and basalts is in silica content and their rates of cooling. A basalt is about 53% SiO2, whereas granite is 73%. Intrusive, slowly cooled inside the crust.
