HELP In a certain species of plant, flowers can be purple or white. When a plant with white flowers is crossed with a plant with purple flowers, all of the offspring have purple flowers. Describe the relationship between the alleles for flower color for the plant.

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

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

Common symptoms of an iron-defiency anemia include muscle weakness shortness of breath and lightheadedness why does iron deficiency causes these symptoms