Provide a scientific explanation on how a mutation to the 17th nitrogen base of DNA leads to the formation of sickle cell hemoglobin protein instead of normal hemoglobin protein.

Which of the following occurs after a natural or unnatural disturbance in an ecosystem

Depending on the organism the number of in a cell may change

How much time has elapsed from the very beginning of "the memior of the conquistador bernal diaz del castillo" to the end? a. castillo's whole life b. a quarter of an hour c. a few weeks d. a decade