Final answer:
The statement is true; hair is produced by the hair bulb and is primarily composed of dead, keratinized cells. Hair growth involves the division of basal cells in the hair bulb and their subsequent keratinization, leading to the formation of the hair shaft.
Step-by-step explanation:
The statement that hair is produced by the hair bulb and is composed primarily of dead keratinized cells is True. Hair is indeed a keratinous filament that grows out of the epidermis. The hair follicle is the structure from which hair strands originate, penetrating through the epidermis into the dermis. The basal cells of the hair bulb actively divide and contribute to the formation of the hair shaft by pushing cells outward during hair growth. As these cells are pushed up and away from the hair bulb, they undergo a process called keratinization, becoming fully keratinized or filled with keratin, which is a hard and resistant protein. This process leads to the cells' death. Therefore, the visible part of the hair above the skin, known as the hair shaft, consists of these dead, keratinized cells.