In Yellowstone National Park in Wyoming, the feature called Old Faithful is which type of natural phenomenon?

Introduction / Context:
Yellowstone National Park in the United States is famous for its geothermal features, including hot springs, mud pots, and geysers. Among these, Old Faithful is the most widely known and is often used as an example in geography and earth science questions. Understanding what Old Faithful actually is helps connect the idea of geothermal activity with specific landforms.

Given Data / Assumptions:

• Old Faithful is found in Yellowstone National Park, located mainly in the state of Wyoming.

• The park lies in a region of strong geothermal activity.

• The options list a hot spring, an extinct volcano, a geyser, and an oak tree.

• Old Faithful is known for erupting in a regular pattern.

Concept / Approach:
A geyser is a type of hot spring that periodically erupts, sending columns of hot water and steam into the air. Old Faithful became famous because its eruptions are relatively predictable in timing and height. While Yellowstone also has many non eruptive hot springs and is linked to a large volcanic system deep below, Old Faithful itself is specifically classified as a geyser.

Step-by-Step Solution:
Step 1: Recall that Old Faithful is one of the most famous geysers in the world. Step 2: Remember that it erupts jets of hot water and steam at fairly regular intervals, which led to its name Old Faithful. Step 3: Note that an extinct volcanic cone would be a solid structure, not a regularly erupting water feature. Step 4: Recognise that a simple hot spring without periodic eruptions would not match Old Faithful behaviour. Step 5: Match this understanding to option C, which describes a geyser that erupts at fairly regular intervals.

Verification / Alternative check:
Tourism brochures, documentaries, and park information materials all describe Old Faithful as a geyser. Visitors gather at viewing points to watch its eruptions, which occur many times per day. Photographs show water and steam shooting up from a vent rather than a volcanic cone or a tree. This consistent description across sources confirms that Old Faithful is a geyser.

Why Other Options Are Wrong:

• A hot spring pool is incorrect because, although a geyser is a special type of hot spring, Old Faithful is specifically known for eruptive behaviour, not just a quiet pool.

• An extinct volcanic cone would be a landform made of solidified lava and ash, not a water and steam jet, so it does not match Old Faithful.

• A very old oak tree is clearly unrelated to geothermal activity and is not associated with the Yellowstone landmark.

Common Pitfalls:
Some learners may use the word hot spring loosely for any thermal water feature and forget that geysers are a specific eruptive type. Others may think of Yellowstone mainly as a volcano and mislabel Old Faithful as a volcanic cone. To avoid mistakes, it is helpful to remember that Old Faithful regularly shoots water and steam into the air, which is the defining behaviour of a geyser.

Final Answer:
Old Faithful in Yellowstone is A geyser that erupts at fairly regular intervals.