Want this question answered?
nothing
trade - off
Opportunity cost applies to the statement the choice to do something is the choice not to do something else.
Service means that you are doing something for someone else. Sometimes one will get paid for their services and other times services are given to other people out of kindness.
An opportunity cost means that, in order to do one thing, you must give up something else (those something else's are the opportunity costs). An example of an opportunity cost would be the large amount of money that would need to be invested in order for a company to make itself more environmentally-friendly (like installing solar panels).
I think that's called Symbiosis.
Something which can be clicked in order to navigate to somewhere else?
Metaphor.
nothing
Tools.
Trade it for something else.
Earth is the name we have given to our planet. [It may not be its real name, and may be known as something else. To paraphrase Lewis Carroll]
Mnemonic device
yes
Repository
It was called centigrade.
When choices are made to accept having less of one thing in order to get more of something else, the results are called trade-offs.