In this passage about cultural identity, choose the noun that best completes the phrase: “open to external ______ but holding its roots hard.”

Introduction / Context:
This cloze question completes the description of a culture compared to a tree. The sentence says that it has grown like a tree, “open to external ______ but holding its roots hard.” The noun that fills the blank must represent forces or inputs coming from outside that can shape the culture without uprooting it.

Given Data / Assumptions:

1) The fragment is “open to external ______ but holding its roots hard”.
2) The options are: influences, facts, modifications, institutions.
3) The preceding adjective “open” strongly suggests a common expression.
4) The passage deals with culture interacting with the outside world.
5) The noun should fit naturally with the phrase “open to external …”.

Concept / Approach:
The phrase “open to external influences” is a standard way of saying that a culture or person can be affected or shaped by ideas and practices from outside. “Influences” is the exact word that fits this collocation. While “facts”, “modifications” and “institutions” are all real nouns, they do not combine as idiomatically with “open to external” in this context.

Step-by-Step Solution:
Step 1: Attach each option to “external”: external influences, external facts, external modifications, external institutions. Step 2: Consider the phrase with the preceding “open to”: “open to external influences” is a very common and natural English expression. Step 3: “open to external facts” sounds odd; we usually say “aware of facts” rather than “open to facts”. Step 4: “open to external modifications” is grammatically possible but clumsy and not typical in cultural discussions. Step 5: “open to external institutions” again sounds technical and does not capture the broad sense of ideas, customs and practices. Step 6: “external influences” directly refers to ideas, customs or practices from other cultures that can affect one’s own.

Verification / Alternative check:
Read the full sentence with “influences”: “It has grown just like a tree, open to external influences but holding its roots hard.” This paints a clear picture of a culture influenced by others yet staying rooted in its own traditions. Inserting any of the other options weakens or distorts this clear image.

Why Other Options Are Wrong:
“facts” are pieces of information, not shaping forces in the same broad sense as “influences”. “modifications” focus on changes themselves, not the forces that cause them. “institutions” are organised structures like schools or governments; while they can influence culture, the phrase “open to external institutions” is not conventional in this context.

Common Pitfalls:
A common error is to focus only on the word “external” and pick any noun that could in theory be external, without checking the collocation “open to external …”. English has many fixed or semi fixed combinations, and cloze questions often rely on these. Paying attention to such patterns like “open to external influences” will help you solve many similar questions quickly and accurately.

Final Answer:
The noun that best completes the sentence is influences.