The polymerase chain reaction can only be used to amplify genes that have already been cloned and sequenced. Why is this true?

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 maintain homeostasis when a persons internal body temperature is 97.5°f

Dna replication or repair occurs in a cell in all of thw following situations except when