B. Smell T-65. Most primitive sense. Goes directly to brain. Smell or olfaction involves a sequence of biochemical activities that trigger neural impulses. Pheromones are chemical substances used as communication within a species to signal relevant stimuli.
Humans use primarily for taste.
Some evidence humans may also secrete and sense sexual pheromones. The Other Senses cont. The Other Senses cont. Touch and skin senses include sensations of pressure, warmth, and cold that are produced by direct stimulation from external objects. We could not survive without this sense.