Final answer:
Fibrosis is the chronic hardening and shrinking of connective tissue, characterized by the accumulation of collagen fibers. It can be caused by factors like inflammation, aging, and diseases such as fibrodysplasia ossificans progressiva.
Step-by-step explanation:
Chronic hardening and shrinking of connective tissue is known as fibrosis. Fibrosis occurs due to the accumulation of collagen fibers in the connective tissue, leading to a loss of elasticity and reduced function. This process can be caused by various factors, including inflammation, aging, and certain diseases like fibrodysplasia ossificans progressiva.