Answer:
The right answer to this question is option A) island forms and mainland forms descended from common ancestors.
It's known in science that a long time ago, all the continents were only one, united all together in a bigger one. This can be observed by the way every continent can fit another one.
A proof of that too, is evolution, when we find organisms in an island that share some characteristics with organisms from another island, that can mean some things, they come from the same place, or these islands share characteristics that lead these organisms to be this way through evolution.
Answer:
D). genetic drift
Explanation:
Genetic drift is the change in an allele frequency over a period of time. This event has to be random and a chance event.
For example: In a population of a flowering plant there are two types of flowers, blue and yellow. Due to a fire many yellow flowers are destroyed by chance. Now the resultant population will have more blue flowers and when they reproduce the population will eventually evolve to have more blue flowers. Effect of genetic variation is more pronounced in a small population since its easy to disturb the allele frequency.
