What is the purpose of “roles” and how does that help make a underwater engineer team to be successful?

Ocean engineers design, build, test, and refine instrumentation and equipment that can operate in offshore and/or coastal environments. ... The work of ocean engineers also plays an important role in oil and gas, military, and marine navigation sectors.

Explanation:

martians or other types of aliens represent a unique fear as opposed to zombies. vampires and other types of monsters.   in most sci-fi stories, aliens come from other worlds and have different or more advanced technology.   abductions and experimentation on human bodies that involve these technologies, or the use of these technologies against human beings and the use of unknown "powers", are a type of fear that's different from that of other types of monsters.