Does anyone know what the expression is?

Which letters from the table represent like terms? a and b b and c a and d b and d

Agroup of student volunteers participates in a study designed to assess several behavioral interventions for improving output in a repetitive task. prior to the beginning of the study, all volunteers unknowingly observed, and their output is measured. at the beginning of the study, prior to any intervention, the volunteers perform the same task under the observation of a study administrator, and their overall output increases. which of the following terms describes this phenomenon? a. simpson's paradox b. hawthorne effect are d. novelty effect d. pygmalion effect e. observer-expectancy effect

The table shows the results of a survey on students favorite kind of movie. select the appropriate values to complete the model to find the fraction of students that prefer comedy or action movie.