属于不可控因素的是（)。
禾谷类作物的叶片，根据其生长先后和着生部位，大致可以分为下、中、上三层，一般认为，（)其光合产物供给根系、分蘖、幼叶等营养器官生长为主;（)供给茎秆、穗的生长;（)供给结实器官。
右眼为－7.25DS／－1.25DC×80，左眼一6.50DS／－1.50DC×80，现需矫正内隐斜视8∆，左上隐斜视4∆，则（)。（采用双眼棱镜等量分配的原则)
植物的果实分类：如果按照果皮的性质来划分，分为（)和（)。肉果分为浆果、核果和梨果;干果分为（)和（)。
Refer to the exhibit. EIGRP had converged in AS 1 when the link between router R1 and R2 went down. The console on router R2 generated the following messages:*Mar 20 12:12:06: %DUAL - 5NBRCHANG E: IP - EIGRP 1: Neighbor 10.1.4.3 (Serial0) is down: stuck in active*Mar 20 12:15:23: %DUAL -3- SIA: Route 10.1.1.0/24 stuck - in - active state in IP - EIGRP 1.Cleaning up The network administrator issued the show ip eigrp topology active command on R2 to check the status of the EIGRP network.Which statement best describes the reason for the error messages？（）
