Answer:
Some of the sensation of olfaction is actually one of pain. (Ans D)
Explanation:
Olfactory system is also known as sense of smell, is called the sensory system used for olfaction (smelling). It is known as the special sense, which have directly association with specific organs. Most reptiles, and mammals contains 2 types of olfactory system:
1) Main olfactory system: It helps in detection airborne substances.
2) Accessory olfactory system: It helps in sense fluid phase stimuli.
The correct answer is option B
Deuterosome is a subphylum of animals which means second mouth. It is also a sister clade of the Protostomia.
In deuterostomes the first opening becomes the anus but in case of protostomes the first opening becomes mouth.
The clade of deuterosomes is Echinoderm that is related to chordates.