The journey of bulk cargoes including oil

An oil tanker alongside a pier.

Many ships have large spaces below their decks to hold cargo.  There are two types of these ships. Bulk carriers are built to carry dry cargo and tankers to carry liquids.

What goods are transported in ships called bulk carriers?

Where do these goods go?

Why are some things better transported as bulk items than in containers?

What is the most environmentally safe way to transport goods?