You cannot. You can transfer it from Pokémon Colosseum or Pokémon FireRed or LeafGreen (provided that your starter was Bulbasaur).
No you cannot catch Entei in Pokemon Emerald.
suicune is a rubbish Pokemon, if ya want it its not in emerald, its in Pokemon silver gold ruby and sapphire, ( they got rid of entei raikou and suicune to make way for rayquaza )
You can't catch entei in Pokemon black he is on a different version
Entei, Suicune, and Raikou are not available in Pokemon Emerald, Ruby or Sapphire. They can be brought into the game by trading.
No, you can catch Entei without catching Moltres.
You cannot catch Entei in Pokémon White because it is not available for capture.
Entei!!!
You can't catch one in Pokemon Emerald.
Yes, You can catch Groudon in Pokemon Emerald.
you cant catch entei on Pokemon pearl. entei is a johto Pokemon and Pokemon pearl is a sinnoh game. the only way to getentei is to trade it over from another game games compatible are Pokemon diamond, Pokemon platinum, Pokemon soulsilver and Pokemon heartgold. the last two i am sure you can get entei. (i have seen it in the wild)
You can't catch a Bellsprot in Pokemon Emerald. You trade it from Pokemon Leafgreen!
Sorry... Just... get Gold or Silver and trade.