Wandering why you haven't noticed the EXC signature on your articles after publishing them? That's because the OC have tagged your article as plagiarized.
Plagiarism in a lay man's term is simply used to define when an author publishes a content that has already been published by another.
How To Avoid Plagiarism
The primary way to avoid plagiarism is to be creative enough to write an original content. If necessary that you must copy, make changes to some and give credits to the original creator.
Use Plagiarism checker sites like Grammerly, Plagiarism checker software to check your contents before publishing.
This is really informative, I appreciate that you have out those links. And also please how do we check the EXC mark like someone said in the comments below. PLAGIARISM also depreciation the value of an article or any content