The cell responsible for secreting the matrix of cartilage is the:.

Osteoblast

Explanation:

It is Osteoblast because Osteoblast is a cell tgat come from the bone marrow and for new bones called osteoid and have only one nucleus, it produce and secrete the organic components and inorganic components of bone or cartilage extracellular matrix. It produce new bones which is made from collagen and some proteins.

this protocol describes a detailed procedure for intracellular flow cytometry staining.

b. the carbon cycle ensures living things have a source of hydrogen