Epistasis should be one of your choices.
I was reading and i think the part "is already to graduate"
is wrong.
shouldn't it be "Is already graduating."
An object pronoun takes the place of a noun in the object part of a sentence. Examples of pronouns that replace a female noun are she, hers, her , etc while that of male nouns are he, his, himself, etc. Nouns that are things are replaced by pronouns like it, itself, etc
Answer;
A search engine uses machines to index webpages; a gateway is compiled by experts or librarians.
Explanation;
Gateway pages are pages specially optimized for one search engine and 1-3 keywords. Gateway pages or doorways stand on their own, separate from the rest of a site.
A search engine is a software designed to search for information on the internet.
