Analogous estimating （）.

A．uses bottom-up estimating techniques

B．uses the actual cost of previou similar projects as the basis for estimating the cost of the current project

C．is used most frequently in the later stages of a project

D．summarizes estimates for individual work items

红光有利于植物的光合作用和茎的伸长生长，紫光有利于植物的呼吸作用和茎的加粗生长。