首页
登录
职称英语
All mammals feed their young. Beluga whale mothers, for example, nurse their
All mammals feed their young. Beluga whale mothers, for example, nurse their
游客
2024-01-04
8
管理
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. [br] The word "shielded" in line 22 is closest in meaning to
选项
A、raised
B、protected
C、hatched
D、valued
答案
B
解析
转载请注明原文地址:https://www.tihaiku.com/zcyy/3332511.html
相关试题推荐
TransportfromBayswaterExampleDestinationHarbourCityExpr
HotelbookingenquiryExampleDestination:VancouverHotelname:Holiday【L1】____
HotelbookingenquiryExampleDestination:VancouverHotelname:Holiday【L1】____
HotelbookingenquiryExampleDestination:VancouverHotelname:Holiday【L1】____
AbbeyCarHireChoosethecorrectlettersA-C.Example[br]Whendoesthemanwa
AbbeyCarHireChoosethecorrectlettersA-C.Example[br]Whatkindofcourse
Wright’sEmploymentAgencyRegistrationFormExampleName:HelenShepqrdAddress
Wright’sEmploymentAgencyRegistrationFormExampleName:HelenShepqrdAddress
Wright’sEmploymentAgencyRegistrationFormExampleName:HelenShepqrdAddress
Wright’sEmploymentAgencyRegistrationFormExampleName:HelenShepqrdAddress
随机试题
下列关于郑州商品交易所的表述,正确的有()。A、成立于1993年5月28日B、郑州商品交易所实行公司制C、1990正式推出标准化期货合约D、会员大
【B1】[br]【B5】[audioFiles]audio_eufm_j71_007(20082)[/audioFiles]meant
Gestures,abodylanguageofhumanbeings,______widelyfromculturetoculture.
下列情形属于因系统缺陷而引发的操作风险的是()。A.洪灾损毁了某银行的大量重要账
下列关于产程的叙述,不正确的是A.第一产程,又称宫颈扩张期,初产妇约需8~10小
一住店客人未付房钱即想离开旅馆去车站。旅馆服务员揪住他不让走,并打报警电话。客人
麻醉药品和精神药品的实验单位A.经国家药品监督管理部门批准 B.以医疗、科研或
界定通信市场的两个核心要素是()。A:通信业务和服务区域 B:通信业务和业务资
用人单位对()不服,不能申请行政复议。A.人民法院作出的行政判决 B.劳动争议
D
最新回复
(
0
)