Answer:
non-specific system
Explanation:
The non-specific immune system is the system that works 24 hours a day, 7 days a week and protects you, regardless of the organism you encounter. This system is composed of the general defenses of the organism that work continuously, creating barriers that protect the body from the entry of any pathogen or foreign substance. This system is composed of T cells, which are true killers of pathogens and which guarantee efficient and complete safety.
According to scientists, many years ago their was a supercontinent called "Pangaea." As years went by, the continents slowly drifted apart which is what's today. However, from recent discovers, scientists predict that in about 250 millions years from now the continents will merge again, however this time, in a different order ("Pangaea Ultima"). So the answer to your question is D.
Hope this helps. :D