The respiratory membrane is composed of fused basement membrane of the capillary walls and

A. Final synthesis step of vitamin K production: The final (and major) synthesis of vitamin K is by gut bacteria and liver processes; the urinary system (kidneys) is not the final synthesis site for vitamin K .
B. Filters the blood, removing wastes: The kidneys filter blood plasma (glomerular filtration) to remove metabolic wastes and excess substances .
C. Regulates the pH of the body: The kidneys conserve or excrete H⁺ and bicarbonate and so play a central role in acid–base balance .
D. Excretion of wastes: By forming urine and eliminating nitrogenous wastes and excess electrolytes/fluid, the urinary system excretes metabolic wastes .

A. Muscularis:The muscularis is the smooth muscle layer responsible for peristalsis/segmentation; it contains muscle, not the primary capillary/lymphatic beds for nutrient absorption.
B. Mucosal epithelium: The epithelial layer faces the lumen and absorbs nutrients at the cell surface, but the transport capillaries/lymphatics lie deeper than the epithelium.
C. Serosa: The serosa is the outer connective tissue covering of the gut -it does not contain the nutrient capillaries and lacteals.
D. Lamina propria: The lamina propria (a connective tissue layer within the mucosa) contains blood capillaries and lymphatic lacteals that transport absorbed nutrients.