Which of the following is a characteristic of gravel?

Gravel is characterized by high porosity and high permeability, making it an effective material in various environmental health applications.

Porosity refers to the amount of void space in a material, and in the case of gravel, the larger particle size creates numerous spaces between the particles. This results in high porosity, allowing water and air to occupy these spaces. High permeability, on the other hand, indicates the ease with which fluids can flow through a material. The coarse texture and structure of gravel enable water to move through it efficiently, thus contributing to its high permeability.

These characteristics are significant in areas such as groundwater recharge, drainage systems, and construction, where effective water movement is essential. The ability of gravel to hold significant volumes of water while also allowing it to move freely makes it an ideal choice for various environmental applications.