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
16
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] What does the passage mainly discuss?
选项
A、The care that various animals give to their offspring.
B、The difficulties young animals face in obtaining food.
C、The methods that mammals use to nurse their young.
D、The importance among young mammals of becoming independent.
答案
A
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3332502.html
相关试题推荐
Carforsale(SUV)ExampleAgeofcar:justunder10yearsoldColour:【L1】______
Carforsale(SUV)ExampleAgeofcar:justunder10yearsoldColour:【L1】______
Carforsale(SUV)ExampleAgeofcar:justunder10yearsoldColour:【L1】______
Carforsale(SUV)ExampleAgeofcar:justunder10yearsoldColour:【L1】______
CoursesforinternationalstudentsExampleWritinginfirsttermInsecondter
CoursesforinternationalstudentsExampleWritinginfirsttermInsecondter
CoursesforinternationalstudentsExampleWritinginfirsttermInsecondter
RecyclinginGaea’sGuardiansExampleAim:
RecyclinginGaea’sGuardiansExampleAim:
RecyclinginGaea’sGuardiansExampleAim:
随机试题
[originaltext]Todaywhenamanstepsontothemoon,orsomethingnewandi
[originaltext]Indiansummerisashortperiodofextremelyfairweatherand
[originaltext]M:Let’sgoforapicnicthisweekend.W:Ican’tI’m’afraid.M
Forthefirsttimeinhistory,evolutionhastakenabackseat.Thereisano
检验检测机构应采取措施确保实验室的良好(),必要时应建立和保持相关的程序。
下边四个图形中,只有一个是由上边的四个图形拼合(只能通过上、下、左、右平移)而成
专家认为,造成一些大学生就业困难的原因之一,就是部分大学生进人的将是劳务型、操作
企业集团的联合是多层次的,由处于()的众多企业组成。A.核心层 B.紧密
甲诉乙违约损害赔偿一案由A法院立案管辖,乙在答辩期间届满后未应诉答辩,A法院在一
()是项目能够接受的贷款利率的最高临界点。A.净现值率 B.投资利润率 C.
最新回复
(
0
)