In one stimulus that does not elicit a response is associated with a second stimulus that does; as a result, the first stimulus, also comes to elicit a response. a. operant conditioning b. classical conditioning c. opponent process theory d. sensitization

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