Mr. Slate runs a rock quarrying business. That is, the company digs up rocks and sells them to builders and designers that need stone. Mr. Slate has been hiring his employees at all levels but is discouraged by the fact that very few of his employee spend most of their careers with his firm. He's heard of something called internal labor market that might encourage his employees to stay with the firm longer. What are internal labor markets? Advise Mr. Slate on the changes -- good and bad -- that are likely to happen if he hires using the internal labor market approach.