Final answer:
The two concrete words in the passage that can be detected by the senses are 'backyard' and 'exercise', as they allow visualization of the physical space and activity.
Step-by-step explanation:
In the provided passage, the two concrete words are backyard and exercise. Concrete words are those that refer to objects or experiences that can be detected by the senses. In this case, 'backyard' refers to a specific physical place that can be seen and touched, while 'exercise' refers to a physical activity that can be engaged in and observed. Both words allow the reader to visualize or imagine the scene taking place with the family's dog.