Anything manufactured by Apple!
No, killing the pig is not essential to the survival of the group. There are other ways to obtain food and resources for survival without harming animals.
Reproduction
yes
However, volcanoes are essential to earths survival they act like a safety valve for the planet (it releases pressure)
Chlorine.
Hansen
to ensure the survival of a species.
bow
a need
Three basic necessities that are essential to human survival are food, shelter and water
Yes. zinc is an essential element for human survival. There are so many enzymes there is your body, which have got zinc as essential component. You may or may not need to take extra supplement of the zinc in your diet. There are other trace elements that are there, which are essential for the survival of the human being. Most of them are placed before and after the Iron in periodic table.
Always. It's essential for survival