Answer:
I. and II.
Step-by-step explanation:
Migration can happen for many different reasons.
A forest fire can destroy a natural habitat, forcing the native organisms to move and relocate, thus leading to migration of a species from area to another.
Increased competition for limited resources can also be a factor. If there is too many predators or too many organisms consuming resources, it may force organisms to relocate to another area, thus leading to migrations of a species from a competitive area to a less competitive area.
Individuals who are separated from the rest of the population isn't a migration. Migration refers to a species group, meaning more than 1 individual is moving from one location to the next due to a factor.