Explain why a leaf kept in the light for 24 hours will turn an iodine solution blue-black, whereas a leaf kept in light for 24 hours and then in the dark for 24 hours will have no effect on an iodine solution

An atom of nitrogen had seven protons in its nucleus. how many electrons does it have

Which type of bond forms between water moleculesstrong bondhydrogen bondcovalent bondpolar bond

1. emigration the movement of people from one place to another 2. immigration a situation in which resources are being used up at a faster rate than they can be replenished 3. migration the leaving of one's homeland to settle in a new place 4. overpopulation the movement of people to a new country 5. sustainable development a situation in which the birth rate is not sufficient to replace the existing population 6. underpopulation the ability to meet current needs without reducing the ability to meet future needs 7. unsustainable development the increase in the population of a city 8. urbanization a situation in which the number of people exceeds the available natural resources in an area