Yes, You can catch Groudon in Pokemon Emerald.
You can't catch one in Pokemon Emerald.
No you cannot catch Entei in Pokemon Emerald.
You can't catch a Bellsprot in Pokemon Emerald. You trade it from Pokemon Leafgreen!
You can't catch it in Pokemon Emerald. You have to trade it from Pokemon FireRed or LeafGreen.
There are many Pokemon you catch that are similar in sapphire and emerald but there are many Pokemon emerald can only get and not sapphire.
You can't catch or obtain other trainers Pokemon in emerald.
No you cannot catch Celebi in Pokemon Emerald.
Yes you can catch Jarachi on emerald.
you cant. You can only catch it in Pokemon emerald, but, you cant catch latias in emerald.
In Pokemon emerald you can catch Kyrogo and Groudon but in Pokemon ruby you can only catch Groudon.
You can onl catch LUNATONE in SAPPHIRE but you can catch solrock in emerald