Any condition in an experiment that can be changed is a control variable!!
You control it!!
The associations are involuntary, digestive tract and arteries >> smooth; whereas voluntary, tendons, extensors >> skeletal and electrical nodes >> cardiac.
<h3>What are muscles?</h3>
Muscles are a special type of tissue that has the ability to contract in response to a given stimulus.
There are different three types of muscle fibers: cardiac muscle, skeletal muscle and smooth muscle.
Cardiac muscle and smooth muscle are involuntary muscles, whereas skeletal muscle is a voluntary muscle.
Learn more about skeletal muscle here:
brainly.com/question/1283837
Neutron has no charge, therefore it is neutral
