Kids never stop asking questions. And Kathy Wollard, whose Los Angeles Times syndicated column "How come?" appears in newspapers around the world, never stops answering them. In five years since the first How Come? was published, Ms. Wollard has written hundreds of columns addressing the whys, whats, wheres, and hows sent in by her readers. A direct follow-up to the original How Come?, How Come? Planet Earth is packed with lively, engagingly written,...