You're a team player; nothing great has ever been accomplished with just one person. Anyone who says otherwise is probably a not very nice person, and not someone who you feel the need to be associated with. You make friends for life, and you take those relationships very seriously. Like, blood oath seriously.
There is nothing that has been invented that we cannot live without. Because, for something to be invented we've had to not have had it before. People sure would piss and moan though if the car was taken away....to answer your question.
The life expectancy of a human who has no food or water will depend on their age at the time. A human can live as long as 7 to 10 days without water and up to three weeks without food.