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.
Space per student is not. simply an issue of room size, but rather, the number of students within the space. A. smaller classroom may have sufficient space per student if the class enrollment is small; likewise, a large classroom may not have sufficient space per student if the class.