Me ! "everyone has an inalienable human right to life, even those who commit murder, sentencing a person to death and executing them violates that right. therefore, the death penalty is the ultimate denial of humna rights." correct that sentence . should there be the word "therefore" or not? (sorry for my bad english) you!

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.  

the answer is camped