What is the grain size range that defines sand?

The correct answer defines the grain size range for sand as being from 2 millimeters to 0.06 millimeters. In geological terms, sand is categorized by particle sizes that fall within this range, which makes it distinct from other soil types like gravel, silt, and clay. Sand grains typically allow for drainage and air circulation, making them suitable for various construction and engineering purposes, especially in well drilling and hydrology applications.

To further clarify, the other ranges mentioned do not align with the standard definitions used in the field of geology. The dimensions provided in the other choices either measure too large, such as gravel, or too small, which could classify as silt or clay. Understanding the specific size range for sand is critical, as it impacts the physical properties of soil and rock formations, influencing both water movement and the overall suitability for constructing wells and other structures.