Many forest tree species have multiple archegonia which, after fertilization produce a number of proembryos.许多林木树种都有颈卵器, 受精以后便产生许多原胚.A similar section through the female plant reveals several bottle - shape archegonia , ...
The text is good in parts, but suffers from discontinuity.文章分开看还好,但是问题在于不连贯。discontinuity in the children's education儿童教育的不连贯性Such a discontinuity or stress raiser causes a local increase of stress.此类的不连续性或应力集中源会引起应...