The correct answer is that it is held constant throughout the experiment.
Explanation:
A variable that is maintained constant all through the experiment is known as a control variable, and it is not the main concern in the outcome of the experiment. In an experiment, if there is any kind of change in a control variable it would lead to an error in the correlation of independent variable to the dependent variables, thus, affecting the results.
According to Charles Darwin's theory of evolution by natural selection, organisms that possess heritable traits that enable them to better adapt to their environment compared with other members of their species will be more likely to survive, reproduce, and pass more of their genes on to the next generation.
