The inner walls of small intestine have thousands of finger-like outgrowths. These are called:

Villi

The correct answer is Option (1) – Villi

The inner walls of the small intestine are lined with thousands of finger-like outgrowths called villi. These structures significantly increase the surface area of the small intestine, enhancing its capacity for nutrient absorption. Each villus contains blood vessels and lacteals (lymphatic vessels), contributing to the absorption of nutrients such as sugars, amino acids, and fatty acids during the digestive process. The term "villi" is derived from the Latin word for "shaggy hair," reflecting the microscopic appearance of these structures.