The only independent variable in this experiment is the amount of nitrogen Sarah uses. All of the other variables are dependent on other factor and processes, but Sarah controls the amount of nitrogen that she uses for each plant.
Answer: Abruptio<span> placentae; Placenta Previa </span>
Abruptio<span> placentae or placental abruption is the premature separation of the placenta from the uterus. Individuals having this abruption of the placenta experiences bleeding, uterine contractions, and fetal distress.</span>
Placenta Previa, on the other hand, occurs when the placenta lies low in the uterus and partially or completely <span>covers the cervical opening (cervix)</span><span>. </span>
Origin of species by means of natural selection
