Briefly describe characteristics of the hypothetical ancestral mollusk, and tell how each class of mollusks (Caudofoveata, Solenogastres, Monoplacaophora, Scaphopoda, Gastropoda, Bivalvia, Cephalopoda) differs from an ancestral condition with respect to each of the following: Shell
Radula
Food
Mantle cavity and gills
Circulatory system
Head

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

What is used to keep track of the gamates and possible offsprings combination

How energy flows through each level in this energy pyramid. is all the matter and energy from one level transferred to the next level?