Grass Pokemon are weak against Fire, Ice, psychic, Poison, Flying, and Bug type moves. The effectiveness of these types of attacks may be increased or decreased if the Pokemon has two types. For example, Bulbasaur is a dual Grass / Poison, so Poison attacks are not as effective.
Sudowoodo is a Rock-type Pokémon. Your type advantage against Rock-types include Fighting, Steel, Grass, Ground and Water-type moves. It is resistant against Normal, Flying, Poison and Fire-type moves.
Normal, Fire, Poison and Flying.
Gengar is a ghost/poison type so... ghost and dark types are super effective against ghost types. ground and psychic types are super effective against poison types
Poison and Steel type moves are good against Fairy type Pokemon.
Fire, Ice, Bug, Poison, Flying, Rock types. Parasect is a both a Bug and a Grass Type. The Moves that work best against it are Fire and Flying type moves (4x damage!). After that, it's Poison, Bug, Rock, and Ice moves for double damage.
Grass Pokemon are weak against Fire, Ice, psychic, Poison, Flying, and Bug type moves. The effectiveness of these types of attacks may be increased or decreased if the Pokemon has two types. For example, Bulbasaur is a dual Grass / Poison, so Poison attacks are not as effective.
Sudowoodo is a Rock-type Pokémon. Your type advantage against Rock-types include Fighting, Steel, Grass, Ground and Water-type moves. It is resistant against Normal, Flying, Poison and Fire-type moves.
Normal, Fire, Poison and Flying.
Gengar is a ghost/poison type so... ghost and dark types are super effective against ghost types. ground and psychic types are super effective against poison types
Poison and Steel type moves are good against Fairy type Pokemon.
To an extent. As a ghost type, it gets STAB for ghost type moves which are super effective against psychic types. However, as a poison type it is weak to psychic type moves. If you can hit the opponent's Pokemon before it hits you, you are safe.
Poison moves don't work very well on Rock, Ground, or Ghost Pokemon, and they don't work at all against Steel types... so if you get some of those type Pokemon to fight for you, you should have a good chance of winning. Try using a Pokemon with the move Earthquake, if you have it. Poison is strong against Grass types and Fairy types, so try not to use those types in the battle if you can help it.
Water type moves and Grass type moves. Electric moves will have no effect. Flying types and Pokemon with levitate ability are good as ground-type moves have no effect against them.
Zubat is a Flying and Poison type pokemon so Rock types, Electric types, Ice types, and Psychic types would be great against it.
poison types are good against grass but they are bad against psychic and ground types and also they do no damage against steel so thats why I dont use them unless they have another type.
Strong ground and psychic Pokemon such as Claydol, Metagross, and Tyranitar. Both ground and psychic moves are super-effective against poison. They are both multiplied by 2. A good ground type move is earthquake, but since many poison Pokemon have levitate or are flying, they can avoid this. It depends on dual types, abilities, available moves, etc., of both Pokemon, but the strongest Pokemon against poison Pokemon generally would be the strongest psychic and ground Pokemon. Some excellent psychic and ground Pokemon (strongest is quite subjective, so there's no definite answer) are Metagross and Tyranitar, respectively. Claydol is a strong Psychic and Ground dual-type Pokemon.