Eliza takes care to illustrate in her research report how long she was in the field and how she has minimized observer effects. In her efforts to address these concerns, Eliza is most directly addressing:.a. threats to internal validity. b. threats to external validity. c. ethics concernsd. reliability

d. all of the above are true.

urban company reports the following information regarding its production cost: units produced 37,000 units direct labor $ 30 per unit direct materials $ 35 per unit variable overhead $ 237,000 in total fixed overhead $ 127,000 in total

answer; importance to people; or acceptance;