Which of these structures forms the channel that sound travels through to reach the eardrum?
select one:
a. auditory tube
b. external auditory canal
c. malleus
d. incus

External auditory canal

Explanation: External auditory canal or external acoustic meatus is a passage that leads from the outside head to the eardrum of ear.

The structure of external auditory canal is same in all the mammals, slightly curved tube extending from the outer ear towards eardrum.

This canal is almost 2.5 cm in length with some hairs and sweat glands on the outer side to prevent insects from entering into the ear.

So, the correct answer is external auditory canal.

relative dating involves things like higher layers are most recent than rocks lower in the sequence. this can be extended to the known sequence of fossils. rocks containing rabbit fossils are later than those containing dinosaur fossils.  

absolute dating methods mainly use radioactive elements that have known rates of decay and produce recognizable products. for example potassium 40 decays to produce argon. once a rock has solidified the argon is trapped. by measuring the argon and potassium0 you can get an accurate number for the age.  

some other methods are good for archaeological ages. dendrochronology involves recognizing the sequence of tree rings. the orientation of magnetized particles in baked clay can be used to date a fire.

hope this .. .

b.

hoped i

explanation: