Sections of a chromosome that code for a trait are called what?

Predict the results of a two base insertion or deletion in a strand of dna that codes for a protien, how does this differ from a three base insertion or deletion?

Which example best describes a reflex action? a. eating food when hungry b. coughing when the throat is irritated c. bending down to lift a heavy object d. going for a walk outside

Why are human population trends difficult to predict?