Respiratory System and Transport in Living Organisms

The human respiratory system includes the trachea, bronchi, and lungs, all of which work together to facilitate gas exchange.

The nostrils are the two external openings of the nasal cavity. They serve as the primary entry point for air into the respiratory system.

The trachea is reinforced by C-shaped rings of hyaline cartilage, which prevent the airway from collapsing during inhalation. Other structures like alveoli are too small for such rings.

The pharynx is the muscular tube that connects the nasal and oral cavities to the larynx and esophagus. It acts as a common passage for both air and food.

The trachea is kept open by rings of cartilage. These rings provide structural support to ensure the airway remains patent.

The larynx, or voice box, is located at the top of the trachea. It contains the vocal cords and is essential for sound production.

The trachea is the main airway leading from the larynx to the bronchi. It is commonly referred to as the windpipe.

The trachea bifurcates into two primary bronchi, which lead into the left and right lungs. These tubes further branch into smaller airways.

The pleura is a double-layered serous membrane that surrounds each lung. It reduces friction during breathing movements.

The diaphragm is a dome-shaped muscle that separates the thoracic cavity from the abdominal cavity. It is the primary muscle involved in respiration.

The rib cage is a bony structure that protects the heart and lungs. It is composed of the ribs, sternum, and thoracic vertebrae.

The epidermis is the outermost layer of cells in plant roots, stems, and leaves. It provides protection and regulates gas exchange.

Inside the lungs, the bronchi branch into smaller and smaller tubes known as bronchioles. These eventually lead to the alveoli.

Alveoli are tiny, pouch-like air sacs at the end of the bronchioles. They are the site of gas exchange between the air and the blood.

The walls of the alveoli are extremely thin and are surrounded by a dense network of pulmonary capillaries to facilitate efficient gas exchange.

The endodermis is the innermost layer of the cortex in plant roots. It surrounds the vascular cylinder and regulates the flow of water into the xylem.

Mature mammalian red blood cells (erythrocytes) lose their nuclei and other organelles to maximize space for hemoglobin, which carries oxygen.

A ventilator is a medical device that provides mechanical ventilation by moving breathable air into and out of the lungs for patients who cannot breathe on their own.

White blood cells (leukocytes) are eukaryotic cells and contain a nucleus and nucleolus, unlike mature red blood cells. Bacterial cells are prokaryotic and lack a true nucleus/nucleolus.

White blood cells, specifically B-lymphocytes, are responsible for producing antibodies that recognize and neutralize pathogens.

Amoeba is a single-celled organism. Grasshoppers and planaria are multicellular animals, making option D the correct choice as it identifies that both 1 and 2 are not single-celled.

The normal hemoglobin range for a healthy adult male is typically 13.5 to 17.5 g/dL, and for a female, it is 12.0 to 15.5 g/dL. Option B (12 to 18) is the most accurate range provided.

Xylem is the specialized plant tissue responsible for the transport of water and dissolved minerals from the roots to the rest of the plant.

The cortex is the ground tissue in a plant root or stem that lies between the epidermis and the vascular bundle.

Xylem is the vascular tissue that transports water and minerals from the roots to the upper parts of the plant.