The acoustic reflex protects the ear from intense sounds by:

A. relaying high amplitude vibration through the helicotrema.
B. opening the oval window to transmit vibration.
C. stiffening the round tympanic membrane.
D. transmitting only low-frequency sounds to the brain.
E. contraction of the stapedius and tensor tympani muscles.

E. contraction of the stapedius and tensor tympani muscles.

The acoustic reflex protects the ear from intense sounds by contraction of the stapedius and tensor tympani muscles.

Explanation:

Although there are two middle ear muscles (tensor tympani and stapedius) in humans, only the stapedius muscle contracts in response to sound.

Contraction os stapedius causes a change in the axis of rotation of the stapes footplate, thus increasing the immitance of the middle ear system. This change in conductivity through the middle ear can be measured indirectly as changes in acoustic immitance. This reflex results in decreased sound transmission to trochlea.

Hence the answer is E. contraction of the stapedius and tensor tympani muscles.

b would be the right answer

image result for describe the various types of gene mutationsghr.nlm.nih.gov

the types of mutations include: missense mutation: this type of mutation is a change in one dna base pair that results in the substitution of one amino acid for another in the protein made by a gene. nonsense mutation: a nonsense mutation is also a change in one dna base pair.

explanation: