题目内容
（请给出正确答案）
A．as a result of
B．considering
C．on purpose
D．whatever
简答题官方参考答案
（由简答题聘请的专业题库老师提供的解答）
更多“All living organisms, regardless of their unique identity, have certain logical, chemical,”相关的问题
A、One giant kelp individual
B、A kelp forest plus all of the physical factors affecting it
C、All physical factors affecting a kelp forest
D、A kelp forest plus all organisms living in it
A．as a result of
B．considering
C．on purpose
D．whatever
A．as a result of
B．considering
C．cognizant of
D．whatever
A、Western medicine is based on the physiology and microbiology.
B、Magnetic Resonance Imaging and Captive Test are two common diagnostic methods of western medicine.
C、Chemotherapy is one kind of treatment of traditional Chinese medicine.
D、Microbiology is the study of all living organisms that are too small to be visible with the naked eye.
It was once assumed that all living things could be
divided into two fundamental and exhaustive categories.
Multicellular plants and animals, as well as many unicellu-
lar organisms, are eukaryotic—their large, complex cells
(5) have a well-formed nucles and many organelles. On the
other hand, the true bacteria are prokaryotic cell, which
are simple and lack a nucleus. The distinction between
eukaryotes and bacteria, initially defined in terms of
subcellular structures visible with a microscope, was ulti-
(10) mately carried to the molecular level. Here prokaryotic and
eukaryotic cells have many features in common. For
instance, they translate genetic information into proteins
according to the same type of genetic coding. But even
where the molecular processes are the same, the details in
(15) the two forms are different and characteristic of the respec-
tive forms. For example, the amino acid sequences of vari-
ous enzymes tend to be typically prokaryotic or eukaryotic.
The differences between the groups and the similarities
within each group made it seem certain to most biologists
(20) that the tree of life had only two stems. Moreover, argu-
ments pointing out the extent of both structural and func-
tional differences between eukaryotes and true bacteria
convinced many biologists that the precursors of the
eukaryotes must have diverged from the common
(25)ancestor before the bacteria arose.
Although much of this picture has been sustained by
more recent research, it seems fundamentally wrong in one
respect. Among the bacteria, there are organisms that are
significantly different both from the cells of eukaryotes and
(30)from the true bacteria, and it now appears that there are
three stems in the tree of life. New techniques for deter-
mining the molecular sequence of the RNA of organisms
have produced evolutionary information about the degree
to which organisms are related, the time since they diverged
(35) from a common ancestor, and the reconstruction of ances-
tral versions of genes. These techniques have strongly
suggested that although the true bacteria indeed form. a
large coherent group, certain other bacteria, the archaebac-
teria, which are also prokaryotes and which resemble true
(40) bacteria, represent a distinct evolutionary branch that
far antedates the common ancestor of all true bacteria.
The passage is primarily concerned with______
A．detailing the evidence that has led most biologists to replace the trichotomous picture of living organisms with a dichotomous one
B．outlining the factors that have contributed to the current hypothesis concerning the number of basic categories of living organisms
C．evaluating experiments that have resulted in proof that the prokaryotes are more ancient than had been expected.
D．summarizing the differences in structure and function found among true bacteria, archaebacteria, and eukaryotes
E．formulating a hypothesis about the mechanisms of evolution that resulted in the ancestors of the prokaryotes
How does Organisms Ward off Invaders
The livelihood of each species in the vast and intricate assemblage of living things depends on the existence of other organisms．This interdependence is sometimes subtle，some times obvious．Perhaps the most straightforward dependence of one species on another occurs with parasites，organisms that live on or in other living things and derive nutrients directly from them．The parasitic way of life is widespread．A multitude of microorganisms(including viruses and bacteria，and an army of invertebrates or creatures lacking a spinal column(including crustaceans，insects，and many different types of worms)make their livings directly at the expense of other creatures．In the face of this onslaught，living things have evolved a variety of defense mechanisms for protecting their bodies from invasion by other organisms．
Certain fungi and even some kinds of bacteria create substances known as antibiotics into their external environment．These substances are capable of killing or inhibiting the growth of various kinds of bacteria that also occupy the area，thereby eliminating or reducing the competition for nutrients．The same principle is used in defense against invaders in other groups of organisms．For example，when attacked by disease--causing fungi or bacteria，many kinds of plants produce chemicals that help to ward off the invaders．
Members of the animal kingdom have developed a variety of defense mechanisms for dealing with parasites．Although these mechanisms vary considerably，all major groups of animals are capable of detecting and reacting to the presence of“foreign”cells．In fact，throughout the animal kingdom from sponges to certain types of wornls shellfish，and all vertebrates(creatures possessing spinal column)
there is evidence that transplants of cells or fragments of tissues into an animal are accepted only if they come from genetically compatible or closely related individuals．
The ability to distinguish between“self”and“non-self”，while present in all animals，is most efficient among vertebrates，which have developed an immune system as their defense mechanism．The immune system recognizes and takes action against foreign invaders and transplanted tissues that are treated as foreign cells．
What does the passage mainly discuss？ 查看材料
A.How parasites reproduce
B.How organisms react to invaders
C.How antibiotics work to cure disease
D.How the immune system of vertebrates developed
Certain fungi and even some kinds of bacteria secrete substances known as antibiotics into their environment. These substances are capable of killing or inhibiting the growth of various kinds of bacteria that also occupy the area, thereby eliminating or reducing the competition for nutrients. The same principle is used in defense against invaders in other groups of organisms. For example, when attacked by diseasecausing fungi or bacteria, many kinds of plants produce chemicals that help to ward off the invaders.
Members of the animal kingdom have developed a variety of defense mechanisms for dealing with parasites. Although these mechanisms vary considerably, all major groups of animals are capable of detecting and reacting to the presence of "foreign" cells. In fact, throughout the animal kingdom, from sponges to certain types of worms, shellfish, and all vertebrates (creatures possessing a spinal column), there is evidence that transplants of cells or fragments of tissues into an animal are accepted only if they come from genetically compatible or closely related individuals.
The ability to distinguish between "self" and "nonself", while present in all animals, is roost efficient among vertebrates, which have developed an immune system as their defense mechanism. The immune system recognizes and takes action against foreign invaders and transplanted tissues that are treated as foreign cells.
What does the passage mainly discuss？
A．How parasites reproduce.
B．How organisms react to invaders.
C．How antibiotics work to cure disease.
D．How the immune system of vertebrates developed.
If food is allowed to stand for some time, it putrefies .When the putrefied material
is examined microscopically ,it is found to be teeming with bacteria. Where do these
bacteria come from, since they are not seen in fresh food？ Even until the mid-nineteenth
century, many people believed that such microorganisms originated by spontaneous
(5) generation ,a hypothetical process by which living organisms develop from nonliving matter.
The most powerful opponent of the theory of spontaneous generation was the French chemist
and microbiologist Louis Pasteur(1822-1895).Pasteur showed that structures
present in air closely resemble the microorganisms seen in putrefying materials .He did
(10)this by passing air through guncotton filters, the fibers of which stop solid particles. After
the guncotton was dissolved in a mixture of alcohol and ether, the particles that it had
trapped fell to the bottom of the liquid and were examined on a microscope slide .Pasteur
found that in ordinary air these exists a variety of solid structures ranging in size from
0.01 mm to more than 1.0 mm .Many of these bodies resembled the reproductive
(15)structures of common molds, single-celled animals, and various other microbial cells.
As many as 20 to 30 of them were found in fifteen liters of ordinary air ,and they could
not be distinguished from the organisms found in much larger numbers in putrefying
materials .Pasteur concluded that the organisms found in putrefying materials originated
from the organized bodies present in the air .He postulated that these bodies are constantly
(20)being deposited on all objects.
Pasteur showed that if a nutrient solution was sealed in a glass flask and heated to
boiling to destroy all the living organisms contaminating it, it never putrefied .The proponents of
spontaneous generation declared that fresh air was necessary for
spontaneous generation and that the air inside the sealed flask was affected in some way
(25)by heating so that it would no longer support spontaneous generation. Pasteur constructed a
swan-necked flask in which putrefying materials could he heated to boiling, but air
could reenter. The bends in the neck prevented microorganisms from getting in the flask.. Material
sterilized in such a flask did not putrefy.
What does the passage mainly discuss？
A．Pasteur's influence on the development of the microscope.
B．The origin of the theory of spontaneous generation.
C．The effects of pasteurization on food.
D．Pasteur's argument against the theory of spontaneous generation.
警告：系统检测到您的账号存在安全风险
为了保护您的账号安全，请在“简答题”公众号进行验证，点击“官网服务”-“账号验证”后输入验证码“”完成验证，验证成功后方可继续查看答案！
