Because they are proper nouns.
Examples:
Don Elizalde Building
Regina Building
Yes, in writing, you should capitalize the names of books.
No.
Yes you do.
no you do not capitalize the names of trees
yes because you capitalize all names
Yes, chemical names are typically capitalized.
The nine rules for using capital letters include: 1) Capitalize the first word of a sentence. 2) Capitalize proper nouns, including names of people, places, and organizations. 3) Capitalize titles when they precede names. 4) Capitalize days, months, and holidays but not seasons. 5) Capitalize the first word in a direct quote. 6) Capitalize the first word of a salutation and closing in letters. 7) Capitalize names of specific geographical regions. 8) Capitalize the pronoun "I." 9) Capitalize acronyms and initialisms.
Capitalize them
no you don't have to
Yes.
Yes.Example: Titanic
Yes.