Meaning: Giraffes only eat plants, such as leaves, twigs, and fruits.
Choice of Words: Herbivores are animals that only eat plants.
Meaning: This means that giraffes only eat plants and not animals. They are not meat-eaters.
Choice of Words: Giraffes are the subject of the sentence, and eat is the verb, which means to consume food. Plants are what giraffes eat.
Meaning: This means that giraffes do not eat meat. They are herbivores.
Choice of Words: Giraffes are the subject of the sentence, and are not is a verb phrase that means "do not". Meat-eaters means animals that eat meat.
Meaning: This means that animals that eat plants are called herbivores. Giraffes are herbivores.
Choice of Words: Herbivores is a noun that means animals that eat plants. Eat is the verb, and plants are what herbivores eat.