Why is it essential to operationally define the variables in a study?

Which answer correctly lists the four main types of animal tissue?

Which of these is the most likely way long-term economic growth takes place? a) increases in interest rates b) increases in overall price level c) increases in labor productivity growth d) increases in labor force participation rate

Melissa is fearful of men and refuses to go on dates. her therapist suggests that she is fearful because she was sexually abused when she was young. the therapist's suggestion most clearly reflects a perspective. a.) humanistic b.) behavioral c.) biological d.) psychoanalytic e.) sociocultural