题目

Good morning, class!We know that there are too many net bars around us. The Internet is popular and it makes our lives colorful. Many of us like going online very much because we can learn how to use the computer and get more information from the Internet. We can learn English. We can read some good newspapers and magazines. It can make us clever in playing computer games. We can send E-mails to our friends quickly. We can chat(聊天) freely online with our friends. It can help us get in touch with people from all over the world.But some students spend too much time in playing compute（7分）.下图甲是某农田生态系统模式图，数值代表能量，单位是J／(cm2·y)；图乙是该生态系统中的两条典型食物链，请分析作答：（1）以上生态系统成分中不属于生物群落的是??????? （用字母回答），图甲中的C包含了图乙中的哪些生物？???????????????????????????????????????????????? 。（2）若生产者固定的能量是1 000 J／(cm2·y)，则B捕食A的过程中能量传递效率为???????? ；B固定的能量中用于自身生长发育繁殖的能量是??????? J／(cm2·y)。（3）某同学模拟调查该生态系统中鼠的种群数量，用玻璃进行如下实验：先从布袋里的白玻璃球中随意抓出一把（经清点共15个），并换成相应数量的红玻璃球放回布袋，摇匀后再抓出一把，经清点共12个（其中红色球4个），则布袋中原有玻璃球______个，其中将白球换成红球相当于__?? _ ___。（4）当鼠和昆虫从植物获得相等能量时,蛇的死亡对植物的影响是利_____(“大于”或“小于”)害。