You only need to capitalize the word "billion" if it is the first word of the sentence...or if it is actually someone's name, or any other proper noun.
no
No, you do not capitalize "first birthday" in a sentence.
You only capitalize 'deceased' if it is at the start of a sentence.
You should not capitalize a sentence fragment following a colon.
No you do not capitalize artist in a sentence
no
No, "billion" should not be capitalized in a sentence like "45 billion dollars." It is only capitalized if it is part of a proper noun or at the beginning of a sentence.
You do not capitalize chickenpox in a sentence. The exception is if the word is the first in the sentence.
No, you do not capitalize "first birthday" in a sentence.
You only capitalize 'deceased' if it is at the start of a sentence.
No, you do not capitalize marine biologist in a sentence. (Unless marine is in the beginning of the sentence)
It depends on where you put it in a sentence. Of coarse in the beginning of a sentence you capitalize space but by it's self no you don't capitalize.
Yes, you always capitalize a day of the week.
You should not capitalize a sentence fragment following a colon.
No you do not capitalize artist in a sentence
No, you should not capitalize "anxiety" in a sentence unless it is at the beginning of a sentence or part of a title.
no or at least not any more than i capitalize the word sentence in a paragraph
15 billion is correct unless there is some reason to capitalize the word billion, perhaps in a title.