问题 读图填空题

(4分)美丽的丝绸是由家蚕吐出的丝加工而成的。请回答家蚕发育过程的有关问题:

(1)家蚕发育的正确顺序是: 卵→       →蛹→成虫。

(2)家蚕的发育过程属于        变态发育,与蝗虫相比多了       期。

(3)家蚕的外骨骼不能随着虫体的生长而生长,因此家蚕发育过程中有       现象。

答案

幼虫 完全  蛹  蜕皮

题目分析:家蚕的发育过程为:受精卵→幼虫→蛹→成虫四个时期,由于幼虫与成虫在形态构造和生活习性上明显不同,差异很大,所以发育方式为完全变态发育,蝗虫的发育过程为:受精卵→若虫→成虫三个时期,比家蚕少了蛹时期,因为家蚕体表的外骨骼不能随身体的长大而长大,所以具有蜕皮现象。

点评:解答此类题目的关键是熟知完全变态发育的特点。

单项选择题

When Marine Lt. Alan Zarracina finally did the splits after months of struggling with the difficult pose in yoga class, the limber women around him applauded.
Zarracina, a 24-year-old Naval Academy graduate and flight student, admits he would have a hard time explaining the scene to other Marines. Each class ends with a chant for peace. Then, instructor Nancy La Nasa hands students incense sticks as a gift for their 90 minutes of back bends, shoulder stands and other challenging positions. Zarracina has tried to drag some of his military friends to class, but they make fun of hint. "It’s not necessarily considered masculine,’ he said.
Still, the popular classes, based on ancient Hindu practices of meditation through controlled breathing, balancing and stretching, are catching on in military circles as a way to improve flexibility, balance and concentration. A former Navy SEAL told Zarracina about the class.
The August edition of Fit Yoga, the nation’s second-largest yoga magazine with a circulation of 100,000, features a photo of two Naval aviators doing yoga poses in full combat gear aboard an aircraft carrier. "At first it seemed a little shocking--soldiers practicing such a peaceful art," writes editor Rita Trieger. Upon closer inspection, she said, she noticed "a sense of inner calm’ on the aviators’ faces. "War is hell, and if yoga can help them find a little solace, that’s good,’ said Trieger, a longtime New York yoga instructor.
Retired Adm. Tom Steffens, who spent34 years as a Navy SEAL and served as the director of the elite corps’ training, regularly practices yoga at his home in Norfolk, Va. "Once in a while I’ll sit in class, and everyone is a 20-something young lady with a 10-inch waist and here I am this old guy, ’ he joked. Steffens, who said the stretching helped him eliminate the stiffness of a biceps injury after surgery, said the benefits of regular practice can be enormous. "The yoga cured all kinds of back pains," he said. "Being a SEAL, you beat up your body."
Yoga breathing exercises can help SEALs with their diving, and learning to control the body by remaining in unusual positions can help members stay in confined spaces for long periods, he said. "The ability to stay focused on something, whether on breathing or on the yoga practice, and not be drawn off course, that has a lot of connection to the military," he said. "In our SEAL basic training, there are many things that are yoga-like in nature.

According to Steffens, practicing yoga

A.helps exercisers remain young.

B.is very effective in relieving back pains,

C.helps exercisers realize the potentials of their bodies.

D.are good for forming a habit of doing things in a regular pattern.

单项选择题