Why is this the answer?

The answer is grass because this short and clever riddle paints a wonderful picture of something you see almost everywhere you go outside. Think about what a single, tiny blade of grass looks like. It is very long and thin, which is why the riddle describes it as a "sharp slim blade." Even though it is not a real metal knife that could hurt you, a single piece of grass can feel a little bit sharp if you run your fingers along the very edge, especially at the pointed tip. When you look at the grass in your backyard or at the park, you will notice the flat, stretched shape of each piece. It truly does look like nature’s smallest little sword or blade. Now, let's think about the second part of the riddle: "that cuts the wind." Grass does not have arms or legs, so how can it possibly cut anything? This is where the riddle is being imaginative and uses clever language to describe an action. Grass grows straight up from the earth, but it is not stiff or strong like a big tree trunk. Instead, it is flexible and very light. Because of this, when the wind blows, every single blade of grass sways, bends, and snaps back quickly in the breeze. When you look across a wide field of grass on a day that is a little windy, it appears like the whole surface is moving and slicing right through the air. The riddle uses those perfect words to help you imagine the way the moving air rushes past each individual blade. This creates a rippling or waving effect across the whole field that is quite beautiful to watch. The grass is always interacting with the wind, almost like it is cutting a path or gently separating the air as it moves. The phrase "cuts the wind" is a fun and poetic way to describe how grass dances and stands up to the invisible force of the breeze. This common, yet amazing, plant fits every part of the riddle perfectly.