Final answer:
The classification of herbicides relates to whether they target grassy or broadleaf plants. Glyphosate is a broad-spectrum herbicide affecting both plant types, while atrazine is selective and 2,4-D targets primarily broadleaf plants. The term 'Horizon' in the question does not refer to a known plant type.
Step-by-step explanation:
The question posed relates to the classification of herbicides based on their targeting of either grassy or broadleaf plants and their active ingredients. First, Horizon is not a type of plant, but since grassy and broadleaf plants are mentioned, it's important to identify the correct herbicide for either group.
Glyphosate is a broad-spectrum systemic herbicide that affects a wide variety of plants, including grassy and broadleaf species. Atrazine is a herbicide mainly used to control broadleaf and grassy weeds but is selective to certain crops. 2,4-D is known to affect primarily broadleaf plants and not grassy plants, which are typically monocots. Thus, the correct answer to what type of plant and associated herbicide could not be determined unless 'Horizon' refers to a specific product or context not mentioned.
Based on the information provided, Horizon is classified as a grassy herbicide. The active ingredient in Horizon is glyphosate, which is a broadleaf herbicide. Glyphosate is effective in killing a wide variety of plants, including grasses and broadleaf and woody plants.