The processes of photosynthesis,by which carbon dioxide and

The processes of photosynthesis,by which carbon dioxide and water are combined --in
the presence of chlorophyll and with energy derived from
light-- to form sugars,
require that carbon dioxide from the air enter the plant.
【简析】主谓之间被一个很长的定语从句 by which…隔开.该定语从句（黑体部分）是 对主语 The processes（光合作用过程）的解释.
【译文】在有叶绿素和光能的情况下,二氧化碳和水通过光合作用结合形成单糖.这就
要求空气中的二氧化碳必须进入植物.
--in the presence of chlorophyll and with energy derived from light-- 这个短语里的with是怎么来的,看不懂,前面又有and了.
in the presence of 修饰的是chlorophyll 还是chlorophyll and with energy derived from light