Which of the following is the best definition of a scientific theory? A.
a broad, well-supported explanation of related observations or events
B.
a description of a natural phenomenon that is always observed to occur under specific conditions
C.
a plausible answer to a scientific question that is used to guide research
D.
a highly tentative statement about the natural world that is likely to be significantly changed or discarded

Works together in the synthesis, modification, packaging, and transport of lipids and proteins

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

Restriction enzymes are used in making recombinant dna. describe the role restriction enzymes perform when constructing recombinant dna.