Answer: The correct answer is - 3) olfactory receptors neurons that detect smell. 4) photoreceptors neurons that detect light .
1) and 2) statements are correctly matched in the question..
Olfactory receptors are also called odorant receptors. The olfactory receptor neurons detect smell and thus give a sense of smell to the organism. They are present in the nasal cavity.
Photoreceptor neurons are those that detect light and they are present in the retina of eye.
The primary role of carbohydrates is to supply energy to all cells in the body. Many cells prefer glucose as a source of energy versus other compounds like fatty acids.
