Bone marrow. The inside of your bones are filled with a soft tissue called marrow. There are two types of bone marrow: red and yellow. Red bone marrow is where all new red blood cells, white blood cells, and platelets are made.
Mine is 8m x 7m (3m is 10 feet, so around 27 x 23 feet). This is normal for an Australian classroom, although there's a fair bit of variation.
1. Teaching procedures introduces students to the physical environment and materials of the classroom and how to use and care for them. If you give students time to explore the materials and spaces in the classroom, they will feel a sense of ownership and independence.