Final answer:
Keratinocytes are connected by desmosomes, which are structures that provide durable and flexible connections in tissues prone to stretching and mechanical stress, such as skin and muscles. Option a is correct.
Step-by-step explanation:
Keratinocytes are tightly connected with each other by desmosomes. These specialized structures function like 'spot welds' between adjacent epithelial cells, allowing tissues to maintain integrity even when they are stretched. Desmosomes are located in tissues that undergo strong mechanical stress and must have some flexibility, such as skin and muscle cells.
In human tissues, you would find desmosomes in tissues that are subject to stretching and mechanical stress, like the skin, heart, and muscles. They contain cadherins that connect to intermediate filaments, helping cells attach to each other in a manner that provides durability and flexibility to the tissue.