Oh, dude, like, technically speaking, "narwhal" is not a proper noun, so it doesn't need to be capitalized unless it's at the beginning of a sentence or part of a title. But, you know, if you wanna give those majestic unicorns of the sea a little extra respect, go ahead and capitalize that "N." It's all good either way.
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.
Earth, as in we live on the planet Earth, is supposed to be capitalized. Earth, as in the dirt we walk on, is not supposed to be capitalized.
Usually, yes a phase of the moon is supposed to be capitalized.
No, it shouldn't be capitalized.
No it shouldn't be capitalized.
Yes, America should be capitalized.
no
Yes, "Pterodactyl" is supposed to be capitalized as it is a proper noun referring to a specific genus of pterosaur.
No, but the names of individual languages are capitalized.
Yes, Siamese would be capitalized.
No it shouldn't be capitalized.
No.