In bone formation, the cells that produce the organic matrix are the:

Osteoblasts 

Osteoblasts are cells are responsible for the synthesis of bone formation. They are cuboidal cells that are located along the bone surface that comprises 4-6% of the total resident bone cells. Also, Osteoblast arise from mesenchymal stem cells (MSC) and MSC give rise to adipocytes, myocytes,  Osteoblast and other cell types.

there are 35 white marbles

step-by-step explanation:

y- yellow marbles

4y + 5 = 45

subtract 5 from both sides

4y = 40

divide for from both sides

y = 10

plug in 10 to get 40 yellow marbles then subtract by 5 to get 35 marbles

thus there are only 10 yellow marbles