Which best describes the cell theory?
a. scientists know all there is to know about cells, so the cell theory will not change.
b. as technological advancements are made, the cell theory may change.
c. a theory, once formulated, cannot be changed.
d. the development of a synthetic cell has caused the cell theory to change.

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.