In a stacked bond (the weakest bond), all joints line up ________.

In a stacked bond, all joints align vertically. This type of bond is characterized by its structural weakness because the vertical alignment of joints creates continuous vertical lines without any stagger or overlap. This configuration can lead to increased susceptibility to structural issues such as cracking, especially under load or stress, since there is little to no interlock between the masonry units. In contrast, other types of bonds, such as running bond or Flemish bond, utilize staggered joints to enhance structural integrity by distributing weight more evenly and providing better interconnection between the units. The vertical alignment in a stacked bond emphasizes its specific design features and why it is considered less strong compared to alternatives.