It was a summer afternoon, and the dog was sitting in the middle of the lawn. After a while, it got up and moved to a spot under the tree,  because it was hot. The it is more likely to refer to The dog than a spot under the tree because The dog can go anywhere, likely to compare as movable object.
In "It was a summer afternoon, and the dog was sitting in the middle of the lawn. After a while, it got up and moved to a spot under the tree,  because it was hot. ", The it is more likely to refer to The dog than a spot under the tree because The dog can go anywhere, likely to compare as movable object.
This example is False.