1. In a correct histogram, the bars should be adjacent to each other without gaps, as the data is continuous. The diagram shows gaps between the bars, which is incorrect.

2. In a histogram, the area of each bar should represent the frequency of the data. This requires using frequency density, calculated as \(\text{Frequency Density} = \frac{\text{Frequency}}{\text{Class Width}}\). The diagram does not use frequency density, leading to incorrect bar heights.