MCQ Detailed View

In biology, a tissue is a group of similar cells that perform a specific function together. Human bodies are made up of cells, tissues, organs, and organ systems, with tissues acting as a middle layer between cells and organs.

Among the given options, blood is considered a tissue. It is classified as a connective tissue because it connects different parts of the body by transporting oxygen, nutrients, hormones, and waste products. Blood is made up of specialized cells, including red blood cells (RBCs), white blood cells (WBCs), and platelets, all suspended in a liquid called plasma. Each component of blood has a specific function: RBCs carry oxygen, WBCs defend against infections, and platelets help in clotting.

On the other hand, lungs, kidney, and pancreas are organs, not tissues. An organ is a structure made up of multiple types of tissues working together to perform complex functions. For example, the lungs contain epithelial tissue, connective tissue, and smooth muscle tissue, all working together for respiration. Similarly, the kidney contains epithelial tissue for filtering blood and connective tissue for structural support. The pancreas has glandular tissue to produce hormones like insulin and exocrine tissues to produce digestive enzymes.

Blood is unique because it is a fluid tissue, unlike solid tissues such as muscle or connective tissues. Its liquid form allows it to circulate throughout the body, linking different organs and systems. This makes blood vital for maintaining homeostasis, immunity, and overall body function.

Therefore, the correct answer is Blood (Option 1), as it is a true example of a biological tissue, whereas the other options are complete organs made up of multiple tissues.