[单选题]招标投标法第三条所称工程建设项目，是指工程以及与工程建设有关的货物、服务。所称工程，是指建设工程，包括建筑物和构筑物的新建、改建、扩建及其相关的（）等
A.装修、技改、保养
B.装修、拆除、修缮
C.技改、拆除、保养
D.装修、拆除、保养

Stomach secretion are composed of four substances: hydrochloric acid, pepsin, mucus and intrinsic factor. (2`)
(1)Hydrochloric acid is important because it kills bacteria contained within ingested food, begins the breakdown of proteins, converts the inactive pepsinogen into the active enzyme pepsin, helps Fe++, Ca++ absorption in the small intestine and promotes secretion of pancreatic fluid, bile and Small intestinal juice. (2`)
(2)Pepsin breaks down protein to absorb amino acid in the small intestine. (2`)
(3)Mucus serves a lubricative role as well as a protective function against the caustic effects of the hydrochloric acid to gastric wall. (2`)
(4)Intrinsic factor is required for the absorption of vitamin B12 and is the only stomach secretion that is essential. (2`)