A layer of stratigraphy in one location overwhelmingly represents one species, while the same species is discovered in a similar stratigraphic layer fifty miles away. What method is used to provide an estimate of age for this layer and this species?
A. Carbon 14
B. Biostratigraphy
C. Dendrochronology
D. Steno’s law of superposition

Dr. redbull conducts a study to determine whether her new energy drink children perform better on spelling tests. she randomly assigns children to one of two groups: group 1 receives her energy drink and group 2 receives water. she then gives both groups a spelling test and compares the results. which of the following is true about this study? a. group 1 is the dependent variable and group 2 is the independent variable. b. this is a correlational study. c. group 2 is the experimental group. d. the independent variable is the type of drink the children receive.