Final answer:
The middle ear bones that touch the umbo of the tympanic membrane are the incus and malleus (option B). These two bones, along with the stapes, are crucial for transmitting sound vibrations to the cochlea of the inner ear.
Step-by-step explanation:
The question asks which middle ear bones touch the umbo of the TM (tympanic membrane), also known as the eardrum. The umbo is the central point of the tympanic membrane to which one of the ear ossicles is attached. From the options provided, the correct answer is B) Incus and malleus. The malleus (also known as the hammer) directly attaches to the tympanic membrane at the umbo, and the incus (the anvil) is connected to the malleus.
These bones, along with the stapes (stirrup), form the chain of ossicles in the middle ear that transmit sound vibrations to the cochlea. If an individual was born without the malleus, they would have problems hearing because the vibrations from the tympanic membrane wouldn't reach the stapes and be transmitted to the cochlea.