In which quaint town does sleigh bells ring take place?

In which research method does a researcher change the value of one variable to determine how the change affects another variable? a. experiment b. observational research c. survey d. case study

Which line is pointing to the myelin sheath? a. 1 b. 2 c. 3 d. 4 awne select the best answer from the choices provided ο α @

Donald is studying the eating habits of all students attending his school. he samples the population by dividing the students into groups by grade level and randomly selecting a proportionate number of students from each group. he then collects data from the sample. which type of sampling is used? select the correct answer below: systematic sampling convenience sampling stratified sampling cluster sampling