The word angels is a common plural noun. It is not capitalized unless the first word of a sentence.
Yes, "Heaven" should be capitalized in the middle of a sentence as it is a proper noun when referring to the place considered to be the dwelling of God and the angels in many religious traditions.
No, "secondary students" should not be capitalized in the middle of a sentence unless it is a proper noun or at the beginning of a sentence.
No, "polar" should not be capitalized when used in the middle of a sentence. It should only be capitalized if it is the first word of a sentence or part of a proper noun.
No, "sister" is not capitalized in the middle of a sentence unless it is used as part of the name or title that is capitalized. For example, in "I have a younger sister," "sister" would not be capitalized.
no
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.
Dodgeball is capitalized if it starts the sentence. But if dodgeball is used in the middle of a sentence it is not capitalized.
No it shouldn't be capitalized.
No, "methadone" should not be capitalized unless it is at the beginning of a sentence or part of a proper noun (such as a specific brand name).
Angel should only be capitalized if it is a proper noun. If you are referring to Angel from Buffy Slayer, than yes. If you are referring to an angel from heaven, than no.
No it shouldn't be capitalized.
Yes, "Middle Ages" should be capitalized when referring to that specific historical period, as it is a proper noun.
No, "secondary students" should not be capitalized in the middle of a sentence unless it is a proper noun or at the beginning of a sentence.
no
Yes.
No it shouldn't be capitalized.
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, "sister" is not capitalized in the middle of a sentence unless it is used as part of the name or title that is capitalized. For example, in "I have a younger sister," "sister" would not be capitalized.