Suitably impressed, an editor will present your book to a marketing committee. If the marketing people think they can sell it, it will get published. That's why you need to research publishers before you submit. To begin with, there are hundreds of publishers of kids books. They range in size from small publishers that publish a handful of books each year to the giants of the industry which churn out hundreds of new titles.
Some major houses are actually a collection of several different imprints.
Each of these smaller units publishes dozens of new books. Catalogs come out in the fall and then again in the spring. Each imprint features a different range of books that reflects the philosophy or outlook of the managing editor. In the universe of companies that specialize in nonfiction, there are other subdivisions. These subgroups of publishers include those who concentrate on science, crafts, and biographies to name only three.