Which of the following fibers are produced by fibroblasts of loose connective tissue and provide it with flexibility?

The fibers that are produced by fibroblasts of loose connective tissue and provide it with flexibility are called Collagen and Elastin fibers.

Step 1: Understanding the question The question is asking about the type of fibers produced by a specific type of cell (fibroblasts) found in a specific type of tissue (loose connective tissue) that gives the tissue its flexibility.

Step 2: Identifying the cells and tissue Fibroblasts are a type of cell that produces collagen and the extracellular matrix, they are found in many types of connective tissues. Loose connective tissue is a category of connective tissue which includes areolar tissue, reticular tissue, and adipose tissue.

Step 3: Identifying the fibers The fibers produced by fibroblasts that give loose connective tissue its flexibility are collagen and elastin. Collagen fibers provide strength and cushioning to many different areas of the body, including the skin, tendons, and ligaments. Elastin fibers provide elasticity to tissues and organs.

So, the answer to the question is Collagen and Elastin fibers.