Which of the following is the definition of ecology? a. the social movement with a goal to protect the environment b. the recycling of human-made materials to reduce waste going into landfills c. the study of interactions among organisms and between organisms and their environment d. the philosophy of living with reduced impact on the earth

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.