The germ theory of disease eventually led to the development of

The germ theory of disease eventually led to the development of certain types of vaccines. This theory explains that specific type or types of microorganisms, which are bacteria, virus, fungi, or protest species, cause some diseases. These organisms can enter the human body, and can even grow and reproduce, causing infection, inflammation to specific organs in the body, and others. One particular vaccine developed successfully through this understanding is the smallpox vaccine, which is an important vaccine up to this day.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be