Why would it require greater force to start a refrigerator moving than to start a dog moving?

Because most refrigerators have greater mass than most dogs have, so greater force is required to achieve the same acceleration.

The purpose of a lab is to do your "expirements" the importance of the topic is so you can now what the story is about and the last one is because no one is me with my question ( what is 3 over 4 x - 9 = 27 maybe you can )