How many types of bone marrow are there?

1. Marrow fills the interior of most bone. 2. One kind is yellow and one is red. 3. There are two types of bone marrow, yellow marrow and red marrow. 4. So the answer is two. _Source: OpenStax 'Anatomy and Physiology 2e', Ch 6 'Bone Tissue and the Skeletal System'_