Why are multiple trials necessary in scientific investigations?

According to the cladogram, which organisms have roundworms as a common ancestor?

Biology ! the conversion of inorganic carbon to organic carbon by plants during photosynthesis is known as _[blank]_. filtration immigration reabsorption primary production

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.