In March 2015, the American space program sent astronaut Scott Kelly to live on a space station for a whole year, where he will not feel gravity as the space station orbits Earth. Scott Kelly’s twin brother, Mark, stayed at home. Scientists then plan to study the twins’ body chemistry, genetics, sight, and other data. This way, scientists can find out how living with and without gravity affects two identical people. What will most likely be a limitation for other scientists trying to recreate this study?

There are ethical controversies over testing human subjects.
There are probably very few astronauts with twin siblings.
There are too many complexities involved in studying body chemistry, genetics, and sight.
There is probably not enough technology to keep someone in space for an entire year.

the answer is b:   the american composer and singer bob dylan composed many songs, by which he is very famous and considered one of the mosts influencial artists of pop music. he was awarded the nobel prize in literature for his type of poetry. but the huge impact his songs had are due to both lyrics and music, without which the message would lose strength.

answer: dinner and a movie with your friends this saturday night.

opportunity cost refers to the benefits that a person or business misses out on when choosing one alternative over another. opportunity costs are easy to miss, but they can be important for decision-making. in this example, the alternative that the person will miss out on is the opportunity to have dinner and watch a movie with friends on saturday, as he will have no money left after buying the cd.

i think your answers would be c and d☺

true, if that is the context. if not, then setting. setting does not always mean surrounding, but also senses. what you hear, see, small, taste, and feel is all a part of the setting.