Answer:
Migration.
Step-by-step explanation:
Migratory species are species that migrate to other countries, hemispheres and even continents, at certain times of the year. The two main cause of migration are food and climate.
When a species migrates too much, it is difficult to protect them, since they will keep changing locations, and there will be a different problem in each one of them.
Hope it helped,
BiologiaMagister