首页
登录
职称英语
The most popular organic gem is the pearl. A pearl is the response of a mari
The most popular organic gem is the pearl. A pearl is the response of a mari
游客
2025-02-03
43
管理
问题
The most popular organic gem is the pearl. A pearl is the response of a marine mollusk to the presence of an irritating impurity accidentally introduced into its body; a cultured pearl is the result of the intentional insertion of a mother-of-pearl bead into a live mollusk. Whether introduced accidentally or intentionally, the pearl-making process is the same: the mollusk coats the irritant with a substance called nacre. Nacre is composed chiefly of calcium carbonate. Because very few natural pearls are now on the market, most pearls used in fine jewelry are cultured. These include "Biwa" pearls and most other freshwater pearls. Cultured pearls are not easily distinguished from natural pearls except by an expert. [br] Nacre is a substance that is ______
选项
A、mechanically manufactured
B、the result of laboratory testing
C、organically secreted by the mollusk
D、present in the chemical composition of freshwater pounds
答案
C
解析
文中第三句(Whether introduced accidentally or intentionally,the pearl-making process is the same:the mollusk coats the irritant with a substance called nacre.)说明无论是天然珍珠还是人工养殖的珍珠,它们的形成过程是一样的:贝类用一种被称之为珍珠质的物质将刺激性的杂物包裹住。由此推断出珍珠质nacre是贝类the mollusk滋生分泌出的,所以选项C正确。
转载请注明原文地址:https://tihaiku.com/zcyy/3940801.html
相关试题推荐
Themostpopularorganicgemisthepearl.Apearlistheresponseofamari
Themostpopularorganicgemisthepearl.Apearlistheresponseofamari
Themostpopularorganicgemisthepearl.Apearlistheresponseofamari
Themostpopularorganicgemisthepearl.Apearlistheresponseofamari
Electronicmailhasbecomeanextremelyimportantandpopularmeansofcommu
Electronicmailhasbecomeanextremelyimportantandpopularmeansofcommu
Electronicmailhasbecomeanextremelyimportantandpopularmeansofcommu
Electronicmailhasbecomeanextremelyimportantandpopularmeansofcommu
Electronicmailhasbecomeanextremelyimportantandpopularmeansofcommu
Electronicmailhasbecomeanextremelyimportantandpopularmeansofcommu
随机试题
市场反需求函数为P=a-bQ,有N(N≥3)个同质企业,典型企业i的成本函数为T
在()中,虚拟工作只能出现在网络图的起点节点和终点节点处。A:双代号网络图
A.午后低热 B.身热不扬 C.发热重,恶寒轻 D.高热不退 E.日晡潮
以下不属于基金管理人内部控制原则的是()。A.有效性原则 B.经济性原则
某时点市值最大的15只股票的市值分别为420亿元、318亿元、306亿元、275
下列有关代谢的表述错误的是A.药物被机体吸收后,在体内各种酶和肠道菌从环境作用下
存款合同中的债务人是()。A.储户 B.存款机构 C.银行柜员 D.存款单
甲在网络散布乙的不实信息,对乙进行诽谤,乙与之理论不成,将甲打成重伤。乙向公安机
固定桥修复牙列缺损的生理基础是A.患者比较舒适 B.满足患者的美观要求 C.
信托行为成立的前提和基础是()。A.委托 B.资金 C.信任 D.股权
最新回复
(
0
)