4 Mathematics books, 3 Chemistry books, 2 Physics books, and 1 Biology book are to be arranged on a bookshelf. How many different arrangements are possible if i. the books in each particular subject...

4 Mathematics books, 3 Chemistry books, 2 Physics books, and 1 Biology book
are to be arranged on a bookshelf. How many different arrangements are possible
if
i. the books in each particular subject must all stand together,
ii. only the Chemistry books must stand together?