Which of the following layers of the epidermis is where keratinization of the cells begins?

A. Mature adipose cells are highly mitotic:Mature adipocytes do not actively divide. Instead, new adipocytes are formed from precursor cells, and mature ones primarily increase in size rather than number.

B. Its primary function is to store triglycerides:Adipose tissue serves mainly as an energy reservoir by storing triglycerides. It also provides insulation, cushioning, and contributes to endocrine functions by releasing hormones like leptin.

C. Most of the cell volume is occupied by the nucleus:In adipocytes, the nucleus is pushed to the periphery of the cell by a large lipid droplet. The majority of the cell volume is taken up by stored fat, not the nucleus.

D. It is composed mostly of extracellular matrix:Unlike connective tissues such as bone or cartilage, adipose tissue has relatively little extracellular matrix. The tissue is mainly composed of densely packed fat cells.

A. within the cartilage divide and secrete new matrix:Chondroblasts are immature cartilage cells responsible for producing and secreting the extracellular matrix, including collagen and proteoglycans. They actively divide and contribute to cartilage growth, especially at the periphery (appositional growth).

B. remain in compact bone even after the epiphyseal plate closes:This description more closely matches osteocytes in bone, not chondroblasts. Chondroblasts are specific to cartilage and do not persist in compact bone after growth plates close.

C. are mature cartilage cells located in spaces called lacunae:This describes chondrocytes, the mature form of cartilage cells that reside in lacunae and maintain the matrix, rather than actively secreting it like chondroblasts.

D. never lose their ability to divide:Chondroblasts can divide while immature, but once they mature into chondrocytes, their division is very limited. Therefore, they do lose much of their proliferative capacity after maturation.