Amniocentesis or amniotic fluid test or AFT refers to the prenatal diagnosis of chromosomal abnormalities and fetal infections. It is performed after 16 weeks of pregnancy. The fetal DNA from a small amount of cells from the amniotic fluid of the amniotic sac is sampled for genetic abnormalities by inserting a needle and extracting it. The fluid contains cells that are sloughed off by the fetus. They are separated from the amniotic fluid, grown in a culture and then microscopically examined for genetic and chromosomal abnormalities. The test is a reliable indicator of chromosomal abnormalities such as Down’s syndrome, spina bifida, muscular dystrophy, rh diseasetrisomy 13, trisomy 18, fragile X, Tay-Sachs disease, Hunter's syndrome and other metabolic disorders.
Dependent and independent variables are variables in mathematical modeling, statistical modeling and experimental sciences. Dependent variables receive this name because, in an experiment, their values are studied under the supposition or hypothesis that they depend, by some law or rule (e.g., by a mathematical function), on the values of other variables. Independent variables, in turn, are not seen as depending on any other variable in the scope of the experiment in question; thus, even if the existing dependency is invertible (e.g., by finding the inverse function when it exists), the nomenclature is kept if the inverse dependency is not the object of study in the experiment. In this sense, some common independent variables are time, space, density, mass, fluid flow rate[1][2], and previous values of some observed value of interest (e.g. human population size) to predict future values (the dependent variable).[3]
Of the two, it is always the dependent variable whose variation is being studied, by altering inputs, also known as regressors in a statistical context. In an experiment, any variable that the experimenter manipulates[clarification needed] can be called an independent variable. Models and experiments test the effects that the independent variables have on the dependent variables. Sometimes, even if their influence is not of direct interest, independent variables may be included for other reasons, such as to account for their potential confounding effect.
Sea otters hide from predators in kelp forests while underwater.
I would have to go with B, since those that had certain traits that wouldn't aid them against the wolves would have been eaten, and those that did would have been able to pass on their genes.
Hopefully this is helpful to you in some way.
