Yes, America should be capitalized.
Yes, the word "Americans" should be capitalized as it is a proper noun referring to the people of the United States of America.
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.
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.
Yes.
Yes.
No.