Why articles being ommited sometime?

Sometime before nouns there’s no definite or indefinite articles like in this sentence (before representatives and congressional districts):

The House of Representative is composed of representatives elected from congressional districts.

Answer

Plural nouns do not require articles. A singular noun does.

There is a singular house and multiple representatives in “The House of Representatives”, which is why house has an article and representatives do not.

“Congressional districts” is also plural, which is why it doesn’t need an article.

Attribution
Source : Link , Question Author : R S , Answer Author : JRodge01