What is experimental probabilitiy?

What type of experiment does only one variable change at a time while all the other variables are kept unchanged? What would cause no water flow at all throughout the house and could it be the pressure tank? How do scientists create models? How could a hypothesis that is proven to be fasle lead to new scientific investigations? How would a scientist do an experiment and a base? What would your life be like if you were a giant? How does the process of convection rely on radiation? A person who is overheated will have a red flushed appearance a person who is chilled will be pale with blue finger tips explain this appearances in terms of the body's control of one of the methods? The space taken up by a cube that is 10 cm on each edge is? What year does MCMXXXV? What are the variable components of air? What angle should you throw a ball or shoot an arrow so that it will fly the farthest and why? What does it mean when nothing shows up on a pregnancy test? What are observable properties of matter? What do you need in an experiment? 21 degrees Celsius is what temperature? Everything is or everything are? What is a reference point assumed to be? What kind of decisions does hypothesis testing help us make? Why do vegetables go soft when you cook them?