Pls help me with both questions i’ll be giving a brainliest to the person with the correct answer

Which term refers to a group or community that forms the focal point of a study and consists of all the people considered for evaluation in the research? a. sample b. population c. variable d. mean

What policy did "jim crow" laws put in place? black codes integration segregation 2. the supreme court case that established the doctrine of "separate but equal" was dred scott v. sandford plessy v. ferguson brown v. board of education 3. the supreme court case that overturned the doctrine of "separate but equal" wasdred scott v. sandford plessy v. ferguson brown v. board of education

Why do you think that historians use the word “revolution” to describe important changes in agriculture? how did the green revolution and other agricultural revolutions change the lives of billions of people? < < read less