Great Marsh? No, but you can get it from Bebe in Hearthome. I think you need the National Pokedex, talk to her, and she'll be quite amazed, and give it to you. Or maybe it's after you talk to her the first time, she'll ask you if you want an Eevee. Either way, you get an Eevee eventually after achieving certain goals.
exeggcute can be found in area 3 in the great marsh
go to the marshes at the great marsh and sooner or later it will appear
It's posible. You can find it in the great Marsh
Carnivine I believe can be found in the Great Marsh in Pastoria city. Well you go in I believe it is on the second or third or sixth area. I am not sure.
After you get the national dex he "might" appear in the great marsh(but he's very rare)
the great marsh is in Pastoria City
great marsh great marsh
the great marsh is in Pastoria City
There is no cave in the Great Marsh.
in the great marsh in the great marsh
talk to people in the great marsh
The Great Marsh, is located inside the Pastoria City.
the pastoria city great marsh
It is on the second floor in the Great Marsh entrance
exeggcute can be found in area 3 in the great marsh
In the great marsh, different pokemon turn up daily and change.
go to the marshes at the great marsh and sooner or later it will appear