Answer: density
Explanation:google
Answer : The ratio of the mass of a substance to its volume is called density. ... The unit of mass is gram (g) and the unit of volume is milliliter (ml). So, the unit of density is g/ml.
The atomic number of H2O is 18 hence it contains 18 protons. Hope this helps.
The density is 1.12161 g/ml
The correct answer among the choices given is option A. Eustachian, Pharynx, Bronchi are structures that ensembles a tube. The Eustachian tube is a narrow passage from the pharynx to the middle ear. Pharynx is a passageway leading from the oral and nasal cavities to the larynx and the esophagus. Lastly, bronchi is an airway in the respiratory tract.