题目

As a young boy my family was very poor. I would often help do something for the neighbors to   16   a little pocket money.       One day I   17   on the door of an elderly woman and asked   18   she needed me to clean the yard. She asked why I was not in   19   and I showed her my worn   20  , which no longer kept me warm. She   21   me to work in the yard. When I finished, she looked at me and said, “I suppose you want to be   22   now.” She then   23   a jar filled with dollar bills and said, “I’m glad you’ve done a   24   job toda图中①代表氧气，②代表二氧化碳，（一）、（二）分别表示植物不同的生命活动过程，请根据图分析回答下列问题：（1）图中a表示根对水分的吸收，吸收的主要部位是根尖的_________，水在b处是由低处往高处流动，其动力主要来自_____________。在炎热的夏季没站在树荫下比站在房屋阴影处感觉更凉爽，说明植物这一生理过程能够降低___________。（2）上图（二）过程进行的场所是在细胞的___________。(3)若光照强度为零，（一）、（二）两个生理过程中不能进行的是_________。