首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
All mammals feed their young. Beluga whale mothers, for example, nurse their calves for some twenty months, until they are about
All mammals feed their young. Beluga whale mothers, for example, nurse their calves for some twenty months, until they are about
admin
2012-08-25
53
问题
All mammals feed their young. Beluga whale mothers, for example, nurse their calves for some twenty months, until they are about to give birth again and their young are able to find their own food. The behavior of feeding of the young is built into the reproductive system. It is a nonelective part of parental care and the defining feature of a mammal, the most important thing that mammals-- whether marsupials, platypuses, spiny anteaters, or placental mammals -- have in common.
But not all animal parents, even those that tend their offspring to the point of hatching or birth, feed their young. Most egg-guarding fish do not, for the simple reason that their young are so much smaller than the parents and eat food that is also much smaller than the food eaten by adults. In reptiles, the crocodile mother protects her young after they have hatched and takes them down to the water, where they will find food, but she does not actually feed them. Few insects feed their young after hatching, but some make other arrangement, provisioning their cells and nests with caterpillars and spiders that they have paralyzed with their venom and stored in a state of suspended animation so that their larvae might have a supply of fresh food when they hatch.
For animals other than mammals, then, feeding is not intrinsic to parental care. Animals add it to their reproductive strategies to give them an edge in their lifelong quest for descendants. The most vulnerable moment in any animal’s life is when it first finds itself completely on its own, when it must forage and fend for itself. Feeding postpones that moment until a young animal has grown to such a size that it is better able to cope. Young that are fed by their parents become nutritionally independent at a much greater fraction of their full adult size. And in the meantime those young are shielded against the vagaries of fluctuating of difficult-to-find supplies. Once a species does take the step of feeding its young, the young become totally dependent on the extra effort. If both parents are removed, the young generally do no survive.
The author lists various animals in line 5 to
选项
A、contrast the feeding habits of different types of mammals
B、describe the process by which mammals came to be defined
C、emphasize the point that every type of mammal feeds its own young
D、explain why a particular feature of mammals is nonelective
答案
C
解析
转载请注明原文地址:https://kaotiyun.com/show/LryO777K
0
托福(TOEFL)
相关试题推荐
Answerthequestionsbelow.ChooseNOMORETHANTHREEWORDSAND/ORANUMBERfromthepassageforeachanswer.Writeyouranswers
Answerthequestionsbelow.ChooseNOMORETHANTHREEWORDSAND/ORANUMBERfromthepassageforeachanswer.Writeyouranswers
Answerthequestionsbelow.ChooseNOMORETHANTHREEWORDSAND/ORANUMBERfromthepassageforeachanswer.Writeyouranswers
Answerthequestionsbelow.ChooseNOMORETHANTHREEWORDSAND/ORANUMBERfromthepassageforeachanswer.Writeyouranswers
Answerthequestionsbelow.ChooseNOMORETHANTHREEWORDSfromthepassageforeachanswer.Writeyouranswersinboxesonyou
TheInnovationofGroceryStoresA.Attheverybeginningofthe20thcentury,theAmericangrocerystoresofferedcomprehen
CompanyInnovationA.InashabbyofficeindowntownManhattan,agroupof30AI(artificialintelligence)programmersfrom
WhichmetalweretheCeltsusingatthebeginningofthefirstmillenniumB.C.?
WhichmetalweretheCeltsusingatthebeginningofthefirstmillenniumB.C.?
Completetheformbelow.WriteNOMORETHANTHREEWORDSAND/ORANUMBERforeachanswer.ProductIncidentReportExampleAnswer
随机试题
患者,女性,28岁。14岁月经来潮,周期正常。现停经45天,阴道流血持续20天,时多时少,无腹痛。妇科检查:宫颈光滑,颈管内有透明分泌物,做涂片见羊齿植物叶状晶体,子宫前位,正常大小,附件未及。可能的诊断是
一类精神药品的处方保存
A.50%葡萄糖注射液B.中药注射剂C.5%葡萄糖注射液D.全肠外营养液E.多潘立酮片根据中国药学会医院药学专业委员会相关标准,将高危药品分为A、B、C三级进行管理属于B级高危药品的是()。
工伤保险中,不得认定为工伤和不得视同工伤的情形包括()。
(2015年)某公司全年需用x材料18000件,计划开工360天。该材料订货日至到货日的时间为5天,保险储备量为l00件。该材料的再订货点是()件。
下面关于单位定期存款的表述中,不正确的是()。
为什么说学校教育在人的身心发展中起主导作用?
按照我国法律规定,共同犯罪人分主犯、从犯、胁从犯和教唆犯。其中,如果被教唆的人没有犯被教唆的罪,对于教唆犯的处罚原则是()。
抵押权,指对于债务人或第三人不移转占有而供担保的不动产及其他财产,优先清偿其债权的权利。根据以上定义,以下属抵押权的是()。
小刘与一妙龄少女发展成为情人关系,其妻小宋知道后满怀怨恨,想找机会杀掉小刘。某日,小宋将毒鼠强拌入菜中等小刘回家吃掉。在等候过程中,看到CCTV12频道正在讲述故意杀人的法律后果,小宋心生恐惧,遂打消杀人念头,将饭菜倒掉。关于小宋的行为,下列哪一选项是正确
最新回复
(
0
)