You see a structural formula in which the symbols for elements are connected by a long dash. you can assume that the chemical bonds in the compound are a ionic b covalent c unstable d metallic

The correct answer is option B, that is, covalent bonds.  

Covalent bonds are more prevalent in organic chemistry in comparison to ionic bonds. A covalent bond comprises of the concurrent attraction of two nuclei for one or more electron pairs. The electrons situated between the two nuclei are known as bonding electrons.  

Covalent bonds take place between different atoms or similar atoms whose difference in electronegativity is not enough to permit the transfer of electrons to produce ions. The covalent bond is demonstrated by either as a solid line or long dash or as a pair of dots.  

b. read the phase at the intersection of any given temperature and pressure.

all matter is made up of atoms

in any element all atoms are the same

elements in a compound are always in a constant ratio: apex