When working with a bunsen burner, which safety rule is most important? a) always add acid to water. b) never wear open-toed shoes. c) make sure to tie your hair back. d) always use a wafting motion to smell chemicals.

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.