I think the answer is Specialized cells!
Answer:
For a change in the environment that surrounds them.
Explanation:
Frogs and toads are amphibians that have the ability to live in both environments, that is why their respiratory system is highly adapted to extreme situations such as sudden climate changes, among others.
This modification of the environment many species would not tolerate because generally species always develop, live and reproduce in a single environment, such as humans, which is only in the terrestrial environment.
It is very difficult for frogs not to be able to adapt or survive climate change since they have the ability to adapt their respiratory system to two totally different media such as water and air.
The answer is B to your question
Multiple things cause the migration of people.
Economic issues arise:
People run out of jobs and opportunities
(BIGGEST REASON)
Cultural reasons:
Forced intentional migration had occurred in the past on accounts of slavery and political instability
Safety:
More popular reason now is because of war or fights with other countries, the people want to keep their family safe so they move them or move with them
Hope this helped
Can you please mention which following. So that I can help you.... ☺️