Difficult to give a comprehensive answer because there are lots and lots of Greek and Roman Gods, particularly because the Romans used to assimilate other deities into their religion as they conquered other countries. This made the transition easier for locals. But I cribbed from another website :
Greek first, Roman second
Aphrodite Venus Ares Mars Artemis Diana Athena Minerva Demeter Ceres
Hades Pluto [conventionally or for a trivia question, but really Pluto, a god of wealth, is the equivalent of a Greek god of wealth called Dis]
Hephaistos Vulcan
Hera Juno
Hermes Mercury Hestia Vesta
Kronos Saturn
Persephone Proserpina Poseidon Neptune
Zeus Jupiter Minor Gods
Erinyes Furiae Eris Discordia
Eros Cupid Fates Morae
Graces Charities
Helios Sol
Hours Horae
Pan Faunus
Tyche Fortuna
Because they are gods and goddesses of different cultures.
Greek mythology came first. Then the Romans came. They admired the gods and goddesses of the Greeks and copied. The Roman gods and goddesses and more disciplined and war-like. Because Greek and Roman mythology things can't have the same name, Romans changed the names.
They were not; they came from two different peoples, and when Romans took over Greece their gods and goddesses were adopted and adapted to the Roman people.
A lot. The Greeks worship many gods and goddesses so you can't find the exact number. There are many major and minor Greek gods and goddesses. You have to be more specific, how many Greek major gods or how many minor gods.
The Greek gods and goddesses typically ate ambrosia and drank nectar.
no
Because they are gods and goddesses of different cultures.
Roman gods and goddesses are pretty much the same, they just have different names.
There are not only a few gods and goddesses. In greek and roman mythology, their are tons of gods and goddesses
In Greek/Roman mythology, the gods are all an extended family.
Many of the Roman gods and goddesses had direct Greek counterparts.
There are lots. Each religion has their own. Add to it the Greek and the Roman gods and goddesses. That's quite a lot.
Greek mythology came first. Then the Romans came. They admired the gods and goddesses of the Greeks and copied. The Roman gods and goddesses and more disciplined and war-like. Because Greek and Roman mythology things can't have the same name, Romans changed the names.
Greek gods, and goddesses drank wine.
It's impossible for a mortal to become a God
They were not; they came from two different peoples, and when Romans took over Greece their gods and goddesses were adopted and adapted to the Roman people.
There is only ever 12 greek gods/goddesses at one time, however many greek believed in roman gods, but the main 15 greek gods/ goddesses are: Aphrodite Apollo Ares Artemis Athena Demeter Dionysus Eros Hades Hephaestus Hera Hermes Hestia Poseidon Zeus