Both the femur and humerus bone have what's called 'spongy bone' inside them and hollow spaces full of yellow and red bone marrow. Additionally, both bones do not attach to the axial skeleton but rather attach to the pelvic or hip bones; while they are both strong bones, they are not made of only compact bone but are made of 'spongy bone' inside them. Lastly, they do not protect any organs but rather allow for movement. D, They both have hollow spaces filled with bone-generating cells, is the best answer in this case
