"The hunter had to contain the dangerous beast."
"The bottles of water contain a total of three liters."
"He could hardly contain his excitement before the race."
Your question is an example, albeit flawed, of a sentence containing the word "atheist."
The subterranean jungles contain lots of flora and fauna. It is a sentence containing the word subterranean.
This question does not contain an intelligible sentence.
"The dog barked loudly."
These substances contain retroactive chemicals in them which are bad for you.
I hope to contain the answer in this sentence. "Contain yourself!", shouted the babysitter. How many words does this question contain? How much information can my brain contain?
Elements can contain plain text, other elements, or both.
He walked around the room like a horse on a carousel.
No. Every sentence requires a predicate (a verb or action word) and this phrase does not contain a predicate.
This supposedly inorganic material just moved.
No such thing in the English Language. A sentence must contain a subject , verb and object. e.g. I saw the aeroplane. 'I' is the subject 'Saw' is the verb (past tense of 'to see'. 'The Aeroplane' is the object. If the sentence does not contain these components then it is not a sentence. NB Saying 'bye' or 'goodbye' on parting is NOT a sentence, but a simple statement.
No, the sentence does not contain a double negative.