Which of the following statements supports the one gene-one enzyme hypothesis?

a) a mutation in a single gene can result in a defective protein.
b) sickle-cell anemia results in normal hemoglobin.
c) multiple antibody genes can code for different related proteins, depending on the splicing that takes place post-transcriptionally.
d) alkaptonuria results when individuals lack multiple enzymes involved in the catalysis of homogentisic acid.

Which statement correctly describes a way that mutations increase the likelihood that a species will survive in a changing environment

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 the following statements most accurately describes convergent evolution? the process in which two similar species evolve separately from each other and share similar characteristics the process in which a single species evolves into two or more new species the process in which two entirely different species evolve in response to each other the process in which two different species evolve separately from each other but still share similar characteristics