How can we taste and smell? place in order the steps involved for flavors on the tongue to create a perceptio in the brain.1) taste receptors are stimulated 2) chemical substances in food dissolve in saliva 3) signals are sent to the thalamus by the facial nerve 4)the gustatory cortex processes taste perception

2) Chemical substances in food dissolve in saliva  

Substances form the food need to be dissolved and and a little bit degraded (by teeth and some of the enzymes in the mouth) in order to react chemically with taste receptors

1)Taste receptors are stimulated  

Taste receptors are located in the oral cavity, usually on the tongue but also pharynx and the epiglottis (receptors are placed on taste buds within papilla on tongue)

3)Signals are sent to the thalamus by the facial nerve  

From the ventral posterior medial nucleus in thalamus sensation is projected to the gustatory cortex

4)The gustatory cortex processes taste perception

The sensation of taste includes: sweetness, sourness, saltiness, bitterness, and umami

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.