What does the arrow mean in the food chain

When should a bar graph be used? a. when there is no independent variable. b. when the independent variable is continuous and does not show a relationship to the dependent variable. c. when the independent variable is continuous and shows a causal link to the dependent variable. d. when the independent variable is composed of categories and does not show a relationship.

Place the steps tor the formation of the enzyme pepsinogen in correct order

Which of these serves as a reference for comparison during a scientific investigation? a)outcome variable (dependent variable) b) test variable (independent variable) c)control group d)hypothesis