Final Answer:
In experiment A, one variable is held constant; in experiment B, another variable is held constant.
Step-by-step explanation:
In scientific experiments, it is common to manipulate and control variables to observe their effects. In experiment A, a specific variable is intentionally kept constant to isolate the impact of the variable being tested. This provides a baseline for comparison.
In contrast, experiment B involves holding a different variable constant, allowing researchers to focus on the influence of the variable under investigation without interference from the held constant variable.
This experimental design is essential for drawing valid conclusions about the relationship between variables. By systematically varying and controlling factors, scientists can establish cause-and-effect relationships and enhance the reliability of their findings.