Final answer:
Intrusive igneous bodies are exposed at the Earth's surface primarily through the processes of weathering, erosion, and uplift. Volcanism is responsible for the creation of igneous bodies, but it does not expose them once they are formed.
Step-by-step explanation:
Intrusive igneous bodies, which are formed beneath the Earth's surface, can take a long time to become exposed at the surface. This process involves several geological activities, importantly weathering, erosion, and uplift. Although volcanism is responsible for the creation of igneous rocks, it does not directly expose intrusive bodies that are already in place beneath the surface. Instead, after the rocks are formed, weathering breaks down the rock on the Earth's surface. Following weathering, erosion transports the weathered material away. This could be through processes such as water flow, wind, or gravity-driven movement like landslides.
Over time, uplift, which can occur due to tectonic processes such as mountain building and continental drift, raises the rock formations closer to the surface. Erosion continues to remove the overlying material. Eventually, this combination of uplift and erosion brings the intrusive bodies to the surface, where they are then subjected to weathering and erosion themselves, which shapes the landscape further.
Therefore, the exposure of intrusive bodies at the Earth's surface is primarily a result of weathering, erosion, and uplift. Volcanism plays a role in the creation of these bodies but not in their exposure after formation.