Grass
Effect
Grass is one of the three basic elemental types along with Fire and Water, which constitute the three starter Pokémon. This creates a simple triangle to explain the type concept easily to new players.
Grass is one of the weakest types statistically, with 5 defensive weaknesses and 7 types that are resistant to Grass moves. Furthermore, many Grass Pokémon have Poison as their secondary type, adding a Psychic vulnerability. The type combination with the most weaknesses is Grass/Psychic.