I think the answer is D, He organized the Louisiana Purchase
Answer:
cross-sectional
Explanation:
Cross-sectional design: In psychological research, the cross-sectional design is referred to as one of the types of "observational study design". A researcher or experimenter while conducting cross-sectional research or study tends to investigate or study the various exposures and outcomes in the different participants or subjects involved in the research at the same time.
In cross-sectional study design, the participants involved in the study differ in "variable of interest" yet share a few characteristics.
In the question above, the researcher is employing a cross-sectional design to her study.
Answer:
The violent phase of Central African colonialism, involving the forced extraction of rubber, ivory, and timber, was followed by a more systematic phase of economic organization. One facet was the establishment of formal plantations on which to grow oil palms and rubber trees.