Final answer:
Dogs have the strongest sense of smell, particularly breeds like Bloodhounds, which have been bred to have enhanced olfactory receptors and larger olfactory epithelia, enabling them to detect scents and perform tasks beyond human capabilities.
Step-by-step explanation:
The strongest dog sense is their sense of smell, also known as olfaction. Dogs have between 800 and 1200 functional genes for olfactory receptors, which is significantly more than the fewer than 400 observed in humans. Some breeds, such as Bloodhounds, have been specifically bred to enhance this sense even further, boasting more olfactory receptors and larger olfactory epithelia than most other dogs.
Dogs' superior olfaction enables them to perform tasks such as tracking scent trails, detecting changes in blood glucose levels, and even identifying cancerous tumors, areas where their olfactory capabilities far exceed those of humans.