Here's why:

* Low Silica Content: Basalt has a relatively low silica content (typically around 45-55%). This makes it more fluid and less viscous compared to rocks with higher silica content.

* Flows Easily: The low viscosity of basalt allows it to flow easily when molten. This is why basaltic lava flows can travel long distances and create extensive lava fields.

Other examples of low-silica igneous rocks include:

* Gabbro: A coarse-grained, intrusive equivalent of basalt.

* Komatiite: A rare, ultramafic volcanic rock with extremely low silica content.

However, basalt is the most common and widely known example of an igneous rock that is both low in silica and flows easily.