¿qué es lo más importante que el autor me está diciendo sobre el tema? o ¿esta idea expresa realmente lo más importante que el autor dice sobre el tema? o ¿cómo puedo saber si esta es la idea principal?

Facial shaving brushes are either bulb-shaped or fan-shaped. an experiment is to be conducted to determine whether the lather thickness is the same for both types of shaving brushes. in previous studies, it was determined that shaving brush size (small, medium, large) is associated with lather thickness, but shaving brush type (wolf whiskers, maggard razors, frank shaving, and so on) is not associated with lather thickness. how could the experiment best be conducted? by blocking on shaving brush size by blocking on shaving brush type by blocking on shaving brush shape by blocking on lather thickness without blocking

How can firms use marginal analysis to determine the price of a product? a) profit maximization can occur when the marginal cost exceeds the marginal revenue. b) the total cost of production can determine the individual unit price of a product. c) marginal analysis can be used to determine at what price profit maximization occurs. d) firms can calculate the marginal cost of a product and set the price lower than the cost.

You are a psychologist who has been asked to write a brief report about the possible causes of anxiety (nervousness, fears, in your report, write up a summary that explains and examines anxiety according to each of the psychological perspectives: psychoanalytic behavioral cognitive humanistic biological sociocultural