In each of the questions given below, a statement with a highlighted phrase is given. Choose the most appropriate replacement from the given options which could replace the highlighted phrase to make the statements grammatically and contextually correct. If the highlighted phrase is already correct then choose option “No replacement required” as your response.

Although we intake diet food, but proper sleep is necessary to be healthy.

The correct option is proper sleep is.

Detailed Explanation:

1. Understanding Conjunction Redundancy:
In English grammar, words like "Although", "Though", or "Even though" are subordinating conjunctions used to introduce a clause of concession. When a sentence starts with a subordinating conjunction like "Although", it does not require a coordinating conjunction such as "but" or "yet" to connect the main clause. Using both "although" and "but" in the same sentence creates a grammatical redundancy (double conjunction error).

2. Analyzing the Original Sentence:
"Although we intake diet food, but proper sleep is necessary to be healthy."
Here, the presence of "but" along with "Although" is redundant and grammatically incorrect.

3. Evaluating the Options:
• proper sleep is: This option removes the redundant word "but" while maintaining the singular subject "proper sleep" with the singular verb "is". This makes the sentence grammatically correct and contextually meaningful.
• but properly sleep is: Incorrect because it retains "but" and incorrectly uses the adverb "properly" instead of the adjective "proper" to modify the noun "sleep".
• but proper sleep are: Incorrect because it retains "but" and uses a plural verb "are" with an uncountable/singular noun "sleep".
• then properly sleep is: Incorrect because "then" is unnecessary and "properly" is used incorrectly.
• No replacement required: Incorrect because the original sentence contains a conjunction error.

Therefore, removing "but" gives the correct sentence: "Although we intake diet food, proper sleep is necessary to be healthy."