Answer:
Step-by-step explanation:
To test what type of exercise will build the most muscle, certain variables need to be controlled in the experiment. The variables that should be controlled are:
1. The starting weight of the participants: By keeping the starting weight of the participants consistent, we can ensure that any changes in muscle growth are due to the type of exercise and not variations in initial muscle mass.
2. The diet the participants eat: Controlling the participants' diet is important because different types and amounts of food can affect muscle growth. By maintaining a consistent diet across all participants, we can isolate the impact of exercise on muscle development.
3. The length of time the participants exercise: Controlling the duration of exercise ensures that all participants are exposed to the same amount of exercise. This allows for a fair comparison between different types of exercises and their effects on muscle growth.
On the other hand, the ending weight of the participants is not a variable that needs to be controlled. It may vary among individuals based on factors such as genetics, metabolism, and other personal characteristics. This variable does not directly relate to the type of exercise being tested and does not need to be controlled.
Therefore, the variables that should be controlled in the experiment to test what type of exercise will build the most muscle are the starting weight of the participants, the diet the participants eat, and the length of time the participants exercise.