Final answer:
In the phrase 'Halloo! You here!', 'Halloo!' is the interjection, which is a word that expresses strong emotions or reactions and can stand alone or be part of a larger sentence.
Step-by-step explanation:
The interjection in the provided example is 'Halloo!' as it is an exclamatory word expressing surprise or joy upon spotting someone unexpected. Interjections in English are words used to express strong emotion or sudden bursts of feeling. They can stand alone, or be incorporated into a larger sentence, and are often followed by an exclamation point when they are expressing a strong emotion.
In the context of the example you've provided from the passage 'Halloo! You here!' cried the Queen addressing Sister Sara.', 'Halloo!' serves as the interjection expressing the Queen's surprise at seeing Sister Sara.
Interjections are an important part of English as they help to convey the emotional tone of the sentence.
Interjections do not grammatically link to other parts of a sentence, which means they can often be removed without altering the structure or meaning of a sentence significantly. Their primary purpose is to convey the speaker's emotional response rather than to convey information.