Which of the following is an essential characteristic of standard modular bricks?

Standard modular bricks are specifically designed to have uniform dimensions, which is an essential characteristic for several reasons. This uniformity in size facilitates easier and quicker installation, as it allows for more consistent alignment and leveling during the construction process. Additionally, it simplifies planning and design, as builders can accurately predict how many bricks will be needed for a particular project and how they will fit together.

The other options do not align with the defining features of standard modular bricks. For example, larger sizes would complicate installation and may not meet the standard requirements builders rely on. Durability is typically more related to the materials and manufacturing processes rather than whether a brick is standard or non-standard. Finally, the usage of bricks is not limited to exterior walls, as standard modular bricks can be employed in both interior and exterior applications depending on the design requirements. Thus, the uniform size is pivotal for efficient construction practices.