In this one word substitution question, you must select the single word that best replaces the phrase "become apparent through the appearance of symptoms", a phrase often used in medical or diagnostic contexts.

Introduction / Context:
This English vocabulary question is about one word substitution. You are given a descriptive phrase, "become apparent through the appearance of symptoms", and you must pick a single word that can replace this entire phrase in a precise and natural way. Such questions frequently appear in competitive examinations to test how well you understand nuanced meanings and usage of English words, especially those used in formal or medical contexts.

Given Data / Assumptions:

• Target phrase: "become apparent through the appearance of symptoms".
• Options: manifest, distinct, visible, divulged.
• We assume the sense is similar to a medical condition or disease becoming evident when symptoms start to show.
• We need a verb or verbal adjective that matches this gradual becoming apparent.

Concept / Approach:
When doctors say that a disease "manifests", they mean that it becomes clear or evident through observable signs or symptoms. The word "manifest" in this context means "to show itself" or "to become apparent". The other options either do not capture the idea of showing through symptoms, or they do not work naturally as a one word replacement for the exact phrase. Therefore, we need to focus on precise dictionary meanings and typical collocations such as "the disease manifests with fever and rash".

Step-by-Step Solution:
Step 1: Rewrite the phrase in simpler form: something is not obvious at first but later becomes apparent through symptoms or signs. Step 2: Recall the meaning of "manifest": to become evident, to show clearly, often used about diseases and conditions. Step 3: Check common usage: "The illness may manifest as a persistent cough" is standard medical English. Step 4: Compare this with the given phrase; both describe the same process of becoming apparent through symptoms. Step 5: Confirm that "manifest" can grammatically replace the phrase in sentences such as "The condition will manifest in early childhood".

Verification / Alternative check:
Test each alternative. "Distinct" means clearly different or separate, not necessarily "becoming evident". "Visible" means something can be seen, but it does not include the idea that it emerges or shows itself through symptoms. "Divulged" means revealed or made known, usually about information or secrets, not about physical symptoms. Only "manifest" is routinely used in medical and general English for something that becomes apparent, especially through symptoms or behaviour.

Why Other Options Are Wrong:
"Distinct" focuses on difference between items rather than the process of appearing through symptoms.

"Visible" refers merely to being seen, and does not convey the specific sense of becoming evident through symptoms.

"Divulged" is used for secrets or confidential information revealed by a person, not for diseases or conditions showing themselves.

Common Pitfalls:
A common mistake is to choose a word that feels vaguely similar, such as "visible", without checking whether it fits technical usage. In exam settings, many distractors are broadly related but not exact synonyms. Always think about example sentences you have actually seen in books, articles, or news reports. In medical or psychological writing, the standard term is that a disease, disorder, or symptom "manifests", not that it is "divulged" or simply "visible".

Final Answer:
The best one word substitute is "manifest".