Answer: -
The first step of the scientific method is
Tiffany observes a change in Hayden's behavior every time she changes the channel.
Explanation: -
The first step of the scientific method is to make objective observations. These observations must be capable of being verified by other scientific minds.
When Tiffany observes a change in Hayden's behavior every time she changes the channel, she makes an objective observation.
This observation can be easily verified by others. It is also free from any personal opinion or beliefs.
Hence it is the first step of the scientific method.