Similarities and differences between frogs and humans eustachian tube

Some modern medical books call this the pharyngotympanic tube. The Eustachian tube or auditory tube is a tube that connects the pharynx to the middle ear. In adults the Eustachian tube is roughly 35 mm long. The human Eustachian tube links phalanx to the middle ear. Whereas, the frog Eustachian tube links its middle ear to its mouth cavity. It is named after the 16th century anatomist Eustachius. 

The Eustachian tube or pharyngotympanic tube is named after the 16th century anatomist Eustachius. In frog, this pharyngotympanic tube connects to the middle ear to its mouth cavity. Whereas, in human, the Eustachian tube links from the phalanx to the middle ear.

the answer is c. it will give up it's valence electron to the other atom.