Extrusive volcanoes, which erupt lava onto the Earth's surface, are notably absent from which one of the following major mountain ranges?

Introduction / Context:
This question belongs to physical geography and the study of mountains and volcanoes. Extrusive volcanoes are those where magma reaches the surface and solidifies as lava flows or pyroclastic materials. Some mountain ranges are strongly volcanic, while others are mainly formed by tectonic collision. Recognising which range lacks active extrusive volcanoes helps students understand plate tectonics and mountain building processes.

Given Data / Assumptions:

• The question asks where extrusive volcanoes are not found.
• Options include Alaska Range, Rocky Mountains, Andes Mountains, Himalayas and the Cascade Range.
• We assume a basic understanding of tectonic plate boundaries and orogeny (mountain building).

Concept / Approach:
Volcanic mountain ranges usually occur along convergent or divergent plate boundaries where subduction or rifting allows magma to reach the surface. Examples include the Andes in South America and volcanic arcs in Alaska and the Cascades. The Himalayas, however, are primarily a result of continent continent collision between the Indian and Eurasian plates, which produces very high mountains but relatively little modern volcanic activity. Therefore, extrusive volcanoes are effectively absent from the central Himalayan range.

Step-by-Step Solution:
Step 1: Identify ranges that are part of active volcanic belts. The Andes are known for many active volcanoes like Cotopaxi and Aconcagua region. Step 2: The Alaska Range and the Cascade Range in North America are also part of the Pacific Ring of Fire with multiple active volcanoes. Step 3: Some segments of the Rocky Mountains have volcanic features or are close to volcanic provinces. Step 4: The Himalayas, in contrast, are mainly fold mountains formed by collision, not by subducting oceanic plates directly beneath the range in a way that produces surface volcanoes. Step 5: Therefore, the correct answer is the Himalayas, where extrusive volcanoes are not found as a major characteristic.

Verification / Alternative check:
Study of world volcano maps typically shows dense clusters along the western edge of the Americas, in Alaska, in the Andes and in the Cascades, but very few active volcanoes inside the main Himalayan belt. Instead, some volcanic activity occurs north of the Himalayas on the Tibetan Plateau or in other neighbouring regions. This clear pattern on global maps confirms that the Himalayas are not a typical volcanic mountain range with extrusive volcanoes.

Why Other Options Are Wrong:
Option A (Alaska Range) is wrong because Alaska is part of the Pacific Ring of Fire and includes several active volcanoes.
Option B (Rocky Mountains) is incorrect; while not as volcanic as the Andes, there are volcanic fields and related activity in and around the Rockies.
Option C (Andes Mountains) is wrong because the Andes form a classic volcanic arc with many extrusive volcanic peaks.
Option E (Cascade Range) is also incorrect, since it includes famous volcanoes such as Mount St Helens and Mount Rainier.

Common Pitfalls:
Some learners assume that very high mountains like the Himalayas must be volcanic, but height alone does not determine volcanic activity. Others may not differentiate between fold mountains and volcanic mountains. To avoid this, it is useful to classify major ranges into categories: Himalayas as young fold mountains formed by continental collision, Andes and Cascades as volcanic arcs, and so on.

Final Answer:
Extrusive volcanoes are not found in the Himalayas.