Which is a property of every mixture?
a. one substance dissolves in another substance.
b. the molecules of one substance break down in the other.
c. different samples of a single mixture have different characteristics.
d. one substance can be separated from another through physical means.

Many organizations release indexes used to measure the development of the world's countries. as we learned in this lesson, these indexes measure many factors, from life expectancy to happiness. in your opinion, what are the three most important factors we can use to determine how developed a country might be? explain your answers in a few sentences.