Why is this the answer?

The answer is stairs because this riddle gives us amazing clues that perfectly describe what stairs do and what they look like. It is a very clever way to talk about something we see every day but might not think much about. Let's look closely at the first clue: "Upon me you can tread, though softly under cover." To "tread" means to walk or step on something. You definitely walk on stairs! The "softly under cover" part is a smart trick. It means the steps are often covered with soft carpet to keep them quiet, or it means the stairs are inside a building, protected by the roof, which is the "cover." Stairs take you from one covered space to another. Next, the riddle says, "And I will take you places, that you have yet to discover." Stairs are like a special, short journey. They take you from the floor you are on up to a new floor, or down to a basement. Each new floor is like a place you can explore and "discover" a new room, a different view from a window, or a hidden corner. They help you reach new heights inside your home or school. The third clue is really smart because it describes the shape: "I'm high, and I'm low, though flat in the middle." Think about climbing a staircase. Each step is higher than the one you just left and lower than the one you are about to step on. They go up and down in a regular pattern. The "flat in the middle" part often means the landing, which is the big, flat platform that sometimes breaks up a very long set of stairs. It is the perfect spot to take a quick rest before you keep climbing. Finally, the riddle says, "And though a joy to the children, adults think of me little." This is a fun clue. Grown ups often just rush up and down the stairs because they are busy and they are not paying much attention. But children sometimes love sitting on them to play, skipping steps, or treating them like a big mountain to climb when they are full of energy. The riddle is trying to trick you by talking about stairs as if they are a person or a living thing that is easy to forget, but all the clues point to the steps in your house.