The peak of Mount Everest is about six miles from its _______

Analyze the question: The sentence needs a word that describes the opposite end of a mountain from its peak. The peak is the top, so we need the word for the bottom of a mountain.

Explain the concept: This is a question on vocabulary and collocation, meaning which words naturally go together.

• The base of a mountain is its bottom, the part where it meets the ground. The usual pairing is "peak/summit" and "base/foot."
• Depth measures how far down something goes, such as the depth of a river or well. It is not used for mountains.
• Source is used for the origin of a river, a stream, or information, as in "the source of the Niger."
• Root is used for plants, teeth, and hair, and it can also describe a word's origin. We say "the roots of a tree," but not the roots of a mountain in ordinary use. (Poets sometimes say "the roots of the mountains," but standard usage prefers "base" or "foot.")

Solution:

1. "Peak" means the highest point.
2. The sentence compares it to the opposite point, the lowest part of the mountain.
3. The standard word for that part is "base."
4. Checking each option: • A. base: fits • B. depth: does not fit • C. source: does not fit • D. root: unnatural in standard English

"The peak of Mount Everest is about six miles from its base" is correct and natural.

Correct answer: A. base

Exam tip: In vocabulary-in-context questions, first work out the relationship in the sentence (here, top and bottom). Then eliminate words that belong to other contexts: depth for water, source for rivers, root for plants. Pair words by their common partners: peak with base, summit with foot, source with river, root with plant.