When a dog is sleeping and does not react to the sound of a person walking around the house, that is most likely an example of?

Dementia.

Explanation:

Dementia is a mental disorder with memory loss, problem-solving, etc. This problem is also found in canines. This disorder occurs due to depression, etc. The symptoms of dementia in canine includes lethargy, sleep disorders, forgetting learned behaviours, etc.

In the given case, the dog who does not react to the sound of a person walking around the house is most likely to suffer from dementia. Dementia causes a canine with the loss of interest in energy and ethusiasm, which is s sign of active canine.

Thus the correct answer is dementia.

the answer is true when observing or determining population size, a direct observation is use, in which each organism is counted in a population or in an area. one benefit of this measure is that you get the exact population count but it will take a long time to  determine  the  size  of a  population.