Yes it should be capitalized.
Yes, "Middle Ages" should be capitalized when referring to that specific historical period, as it is a proper noun.
No, "narwhal whale" does not need to be capitalized in the middle of a sentence unless it is part of a proper noun or title.
No, cardiovascular disease does not need to be capitalized unless it is at the beginning of a sentence or part of a title.
No, the word "region" does not need to be capitalized in a sentence unless it is the first word of the sentence or part of a proper noun (e.g. "Pacific Northwest region").
No, the word "assembly" does not need to be capitalized unless it is part of a proper noun or the first word in a sentence.
No, the word "seismograph" does not need to be capitalized unless it is at the beginning of a sentence or part of a title.
No it shouldn't be capitalized.
Yes, the first letter of the word following a colon should be in lowercase unless it is a proper noun or the start of a complete sentence.
it depends on where you place dolphin in a sentence. If it is the first word of a sentence, then yes, it should be capitalized. If it is in the middle of a sentence, then it does not need to be capitalized.
YES! The State Senator is a very importantperson!
No, it shouldn't be capitalized.
I think you need to give an example; the question isn't clear enough.
No, the word "region" does not need to be capitalized in a sentence unless it is the first word of the sentence or part of a proper noun (e.g. "Pacific Northwest region").
No!
Yes, days of the week are capitalized.
Well, as a common noun it does not need to be capitalized as for it used in this sentence, " I'd like to give you a wedding at my house." but if used as a proper noun it does need to be capitalized. " I loved the Wedding."
Yes, "Biology" should be capitalized because it is a proper noun and the name of a specific scientific discipline.
No.