Moss invades and establishes itself on bare rock, accumulating the beginnings of soil. after several years, enough soil has become established that grasses begin to grow where there was once bare rock. without the moss building up soil, the grasses would have had no chance. the establishment of the mosses on bare rock and eventual addition of grasses represents:

What is the difference between bacterial infections and viral infections?

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

Which of these is one of the nitrogenous bases in dna? a. proline b. leucine c. glycine d. thymine