The olfactory bulb can detect the smell of odor particles.
The nose is the sense organ that has olfactory cells responsible for detecting an odor. These cells are located in the nasal cavity and respond to the molecules in the air that we inhale.
Smell
To attract insects
A ganglia is a collection of nerve cell bodies. The hydra do not have ganglia. Instead, they have special cells for detecting touch.
There are many, many different species of ferns. They are even in several different genuses. Some ferns, such as the Hayscented Fern (Dennstaedtia punctilobula), do have an odor.
The olfactory nerve carries impulses from odor-detecting cells to the brain.
The nose is the sense organ that has olfactory cells responsible for detecting an odor. These cells are located in the nasal cavity and respond to the molecules in the air that we inhale.
The word sought is likely smiling (showing a smile) or smelling (having or detecting an odor).
UniPolar Neuron Cells
Odor is a human sense (or an animal sense), if you lack the organs for detecting it, then a substance is "odorless" ... to you. Note that (for us mammals) a substance must be in vapor form to be detected, thus solids lack odor in general, while heating intensifies odor.
Cones
Sorry we do not know what you mean by "firm odor" so we can not answer your question.
Smell
The main difference between rod cells and cone cells is that the rod cell is responsible for detecting the dim lights only with black and white, and the cone cell is responsible for detecting the bright lights with colors. Also in retina, there are more rod cells than the cone cells. thirdly, defect in rods causes night blindness and defect in cones causes color blindness.
To attract insects
This is actually quite gross .... be warned.Nothing carries odor. The "odor" is actually tiny physical pieces of the item in question that the nose has cells to detect and analyze. So when you are smelling something, you are actually sensing the actual item. So if you smell a flower, you are actually sensing the molocules and other compounds in the oils and other constitutes of the flower. If you smell perfume, its because you are detecting the same thing; the actual oils that constitute the perfume. If you smell pine wood, there are tiny microscopic pieces of wood going in your nose.This also includes bad odors as well....
Esters give many flowers their pleasant odor.