Dr. sullivan is conducting a clinical trial to determine if vitamin xx can improve test performance of students in an introductory college nutrition course. dr. sullivan puts all the students' names in a hat and draws names to determine if they will be placed in the control or the experimental group. the experimental group receives a capsule of vitamin xx and the control group a "sugar pill" that tastes and looks identical to the vitamin xx capsule. neither dr. sullivan nor the participants know who is receiving which treatment. this experiment is best described as

Which civil rights act banned discrimination against any person based on race or color? 14th amendment 15th amendment civil rights act of 1964 voting rights act of 1965

According to the federal regulations, which of the following studies meets the definition of research with human subjects? a. a researcher uses the customs office’s passenger lists for ships bringing immigrants to the us between 1820-1845 to track the numbers of immigrants from certain ethnic groups.b. a researcher conducts a linguistic study of comments posted on a local public blog.c. a developmental psychologist videotapes interactions between groups of toddlers and their care givers to determine which intervention methods most effectively manage aggression.d. a researcher asks the director of a local free clinic about the number of patients in the last two years with newly diagnosed hiv/aids.

The principal effector function of igm is