ANSWERS 12. B collecting ducts 13. B efferent arteriol 15. juxtaglomerular cells 16. A can be active or passive 17. C loop of Henle 18. D proximal convoluted tubule 19. .C increase the surface area of the mucosa of the small intestine 20. D submucosa of the duodenum 21. E myenteric plexus 22. D secretion - gall bladder epithelial cells ( I AM NOT SURE ABOUT QUESTION NO .14 , ) Solution ANSWERS 12. B collecting ducts 13. B efferent arteriol 15. juxtaglomerular cells 16. A can be active or passive 17. C loop of Henle 18. D proximal convoluted tubule 19. .C increase the surface area of the mucosa of the small intestine 20. D submucosa of the duodenum 21. E myenteric plexus 22. D secretion - gall bladder epithelial cells ( I AM NOT SURE ABOUT QUESTION NO .14 , ).