Which description accurately reflects how to test a biological hypothesis using experimental design elements such as controls, variables, replication, and statistics?

• A. Design includes a control group, isolate the independent variable, measure the dependent variable, replicate trials, analyze with statistics to determine significance.
• B. Randomly vary all variables without controls.
• C. Only measure outcomes without replication.
• D. Use no statistics.

Answer: (C)

Testing a biological hypothesis relies on a well-designed experiment that controls extraneous variables, uses a control group, isolates the independent variable, clearly defines and measures the dependent variable, includes replication to estimate variability, and applies statistics to decide if the observed effects are likely not due to chance. The description that includes a control group, isolates the independent variable, measures the dependent variable, includes replication, and uses statistics to determine significance best captures this approach. The other options fall short because they either omit controls, omit replication, or omit any use of statistics, making results unreliable or uninterpretable.