1. The problem involves understanding a 3D block pyramid made of 1 cm x 1 cm x 1 cm cubes, where the base layer has 9 cubes in a row, and each upper layer decreases by one cube until the top layer is a single cube. 2. To find the total number of cubes in the pyramid, we use the formula for the sum of the first $n$ natural numbers, since each layer has one less cube than the layer below: $$\text{Total cubes} = 1 + 2 + 3 + \cdots + 9 = \frac{9 \times (9+1)}{2}$$ 3. Calculate the total number of cubes: $$\frac{9 \times 10}{2} = \frac{90}{2} = 45$$ 4. Therefore, the pyramid consists of 45 cubes in total. 5. The bar graph below shows columns labeled A to G with heights 4, 1, 4, 9, 2, 4 respectively. These represent quantities or measurements related to the problem but are not directly related to the total cube count. Final answer: The total number of 1 cm³ cubes in the pyramid is **45**.