Some nouns are not made plural by adding 's/es'. It is done in a different manner.
Criterion- criteria, mouse- mice, phenomenon- phenomena, radius- radii, syllabus- syllabi, etc.
For example: You don't fulfill the criterions set by the commission.(wrong)
You don't fulfill the criteria set by the commission.(Right)
We need the plural form of the given noun in the sentence i.e. mice.

The given sentence is in Passive Voice. As per the question we have to change it into Active Voice.
The structure of the given sentence as follows: Subject+has/have+V3+Object.
(Active Voice) Subject (Objective Case)+has/have+been+V3+Object (Subjective Case).
(Passive Voice) 'The plan' will be put in place of 'we'.
(Subject becomes object) And 'We' will be put in place of 'The plan'.
(the object becomes subject) 'Have looked at' will be changed into 'Has looked at'.
(To agree with the changed subject and object) Thus the correct sentence is:
The plan has been carefully looked at

In Active Voice, a sentence emphasizes the subject, performing an action. In Passive Voice, a sentence emphasizes the action or the object of the sentence.
The given sentence is in the active voice and 'We' is the subject and 'Liza' is the object.
When we convert this sentence into passive voice, the subject 'We' of the active voice becomes the object 'us', the object 'Liza' becomes the subject.
The passive format "is + V3 (regarded)" should be used. This is the active and passive voice rule for the present simple tense.

Chand Bibi is best known for defending Ahmednagar against the Mughal forces of Emperor Akbar in 1595.

The Ajanta cave paintings mostly belong to the period of the Guptas. There are only two known examples of cave paintings of the the Gupta period in ancient India. One of these is paintings of Ajanta caves.

Muhammad- bin - Tughluq was a brilliant scholar. He was a knowledgeable person and well versed in astronomy, poetry, philosophy, logic, medicine, physical science, and mathematics.

The famous work "Prithviraj Raso" was written by Chand Bardai, in hindi. It was written in Braj Bhasha. An epic poem, it demonstrates the life and contributions of the 12th century king, Prithviraj Chauhan.

In the given sentence, "Pintu has been advised to reduce smoking by his family doctor," the word "advised" is used correctly and does not require substitution.

Explanation:

Pintu has been advised: This part of the sentence indicates that someone (in this case, Pintu's family doctor) gave advice or recommendations to Pintu. "Advised" is the past participle form of the verb "advise," used in passive voice.

to reduce smoking: This infinitive phrase clarifies the advice given to Pintu. He has been advised to reduce his smoking habit, meaning he should smoke less or quit smoking altogether.

by his family doctor: This prepositional phrase tells us who gave the advice, specifying that it was Pintu's family doctor. The preposition "by" indicates the source or origin of the advice.

The sentence conveys the idea that Pintu received advice from his family doctor to cut down on smoking, and the structure of the sentence is correct and clear.