I'm doing an experiment where I wanted to determine which dog food most dogs would choose if they were given a choice. I placed Brand #1 in a bowl and Brand #2 in another bowl 5 feet from the first bowl. I recorded the number of dogs that chose each brand. What are some controlled variables I would have to consider?

Earths energy sources include both renewable and nonrenewable resources. name at least three sources of energy that could be used in your house. then describe the ideal energy source for generating most of your homes electricity, and explain why you chose that source. can someone give me some ideas, i’m kinda confused.