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
12
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 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://tihaiku.com/zcyy/3332503.html
相关试题推荐
CyclingholidayinAustriaExampleAnswerMostsuitableholidaylasts__10__days
CyclingholidayinAustriaExampleAnswerMostsuitableholidaylasts__10__days
CyclingholidayinAustriaExampleAnswerMostsuitableholidaylasts__10__days
CyclingholidayinAustriaExampleAnswerMostsuitableholidaylasts__10__days
CyclingholidayinAustriaExampleAnswerMostsuitableholidaylasts__10__days
CyclingholidayinAustriaExampleAnswerMostsuitableholidaylasts__10__days
CyclingholidayinAustriaExampleAnswerMostsuitableholidaylasts__10__days
TransportfromBayswaterExampleDestinationHarbourCityExpr
TransportfromBayswaterExampleDestinationHarbourCityExpr
TransportfromBayswaterExampleDestinationHarbourCityExpr
随机试题
Conventionalwisdomsaystreesaregoodfortheenvironment.Theyabsorbcar
设随机变量X,Y相互独立,且X~N,Y~N,则与Z=Y-X同分布的随机变量是()
以下有关ADR叙述中,不属于“C型药物不良反应”的是()。A:与本身药理作用无
女性,31岁,GPAL,人工流产3次,月经规律,现继发不孕2年,男方精液检查正常
当事人一方不履行合同债务或其履行不符合合同约定时,对另一方当事人所应承担的继续履
柏拉图认为,国家是放大了个人。教育应该按照国家需要来造就个人,这一观点属于(
从所给的四个选项中,选择最合适的一个填入问号处,使之呈现一定的规律性: A.如
德国教育家赫尔巴特是()的代表 A.儿童中心论a教师中心论 C.劳
某投行在对目标企业估值时采用市销率估值法。假设该目标企业所在行业的标准市销率为1
(2016年真题)依据《通用安装工程工程量计算规范》(GB50856--2013
最新回复
(
0
)