Why can a sound wave be compared to the spread of ripples of water from a stone dropping into a pond?

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.

Which of the following is a limitation of a clinical trial? a.)amount of random assignments b.)hospital cost c.)number of test tubes d.)amount of peer review

Match the correct terms to their descriptions a system in which only energy but not matter is exchanged frozen water in snow part of geosphere that includes only soil a thin layer between the troposphere and the stratosphere cryosphere tropopause closed system pedosphere