首页
登录
职称英语
In the past oysters were raised in much the same way as dirt farmers raised
In the past oysters were raised in much the same way as dirt farmers raised
游客
2025-04-12
9
管理
问题
In the past oysters were raised in much the same way as dirt farmers raised tomatoes-by transplanting them. First,farmers selected the oyster bed,cleared the bottom of old shells and other remains,and then scattered clean shells about. Next they "planted" fertilized oyster eggs,which within two or three weeks hatched into larvae. The larvae drifted until they attached themselves to the clean shells on the bottom. There they remained and in time grew into baby oysters called seed or spat(贝卵). The spat grew larger by drawing in seawater from which they derived microscopic particles of food. Before long,farmers gathered the baby oysters,transplanted them in other waters to speed up their growth,and then transplanted them once more into another body of water to fatten them up.
Until recently the supply of wild oysters and those crudely farmed were more than enough to satisfy people’s needs. But today the delicious seafood is no longer available in abundance. The problem has become so serious that some oyster beds have vanished entirely.
Fortunately,as far back as the early 1900’s marine biologists realized that if new measures were not taken,oysters would become extinct or at best a luxury food. So they set up well-quipped hatcheries and went to work. But they did not have the proper equipment or the skill to handle the eggs. They did not know when,what,and how to feed the larvae. And they knew little about the predators that attacked and ate baby oysters by the millions. They failed,but they doggedly(努力)kept at it. Finally,in the 1940’s a significant breakthrough was made.
The marine biologists discovered that by raising the temperature of the water,they could induce oysters to lay eggs not only in the summer but also in the fall,winter,and spring. Later they developed a technique for feeding the larvae and rearing them to spat. Going still further,they succeeded in breeding new strains that were resistant to diseases,grew faster and larger,and flourished in water of different salinities(盐分)and temperatures. In addition,the cultivated oysters tasted better! [br] In the passage,the author mentions that the new strains of oyster are_____.
选项
A、cheaper
B、shaped differently
C、better textured
D、healthier
答案
D
解析
本题的四个选项中,只有D项为正确答案。这可从文中的"they succeeded in breeding newstrains that were resistant to diseases,grew faster and larger,and flourished in water of different salinities(盐分)and temperatures."推知,即他们进一步成功地培养出了新的品种,可以抵抗疾病、长得更快、更大并且在不同的盐度和温度的水中都能茁壮生长。
转载请注明原文地址:https://tihaiku.com/zcyy/4034444.html
相关试题推荐
Inthepastoysterswereraisedinmuchthesamewayasdirtfarmersraised
Inthepastoysterswereraisedinmuchthesamewayasdirtfarmersraised
Inthepastoysterswereraisedinmuchthesamewayasdirtfarmersraised
Farmersinthedevelopingworldhatepricefluctuations.Itmakesithardto
Farmersinthedevelopingworldhatepricefluctuations.Itmakesithardto
Themassacreofinnocentpeoplecannoteverbecondoned.A、overlookedB、praisedC
Thisyearthefarmerswerejustabletogatherinthe______beforethefinewea
Theactresswasvery______attheinsultingquestionraisedbyheropponentatt
Thesemachineshaveraised______manytimes.A、proficiencyB、frequencyC、efficien
Farmersareallowedtogrowsmallgardensoftheirownandtheyselltheirveget
随机试题
Howmuchshouldthemanpay?[br][originaltext]W:Here’sthestand.M:Ah,yes
[originaltext]M:Didyounoticetheyjustbuiltanothercoffeehouseacrossthe
汉字的书法艺术不仅盛行于中国,也传播到了日本、朝鲜等国,被视为东亚的重要艺术和最优雅的写字形式之一。Calligraphy,asatraditional
[originaltext]W:ArtDepartment,thetreasurerBrownspeaking.M:Hello,Profes
Mrs.Petersstoppedplayingthepianowhe
坚定中国特色社会主义道路自信、理论自信、制度自信、文化自信,说到底就是要坚定(
判断健康风险的高低主要根据( )。A.疾病危险性的高低 B.疾病危险性的平均
继唐太宗之后,武则天也大力提倡科举。有一年,她将应举的人集中到洛阳宫殿,亲自出题
在2013—2016年,我国乡村人口增幅最大的年份是: A.2013年
在无效市场条件下,基金管理人不应当尝试获得超出市场的投资回报,而是努力获得与大盘
最新回复
(
0
)