Câu hỏi:
02/04/2020 214Read the following passage on transport, and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 1 to 7.
(1) The protozoans, minute, aquatic creatures each of which consists of a single cell of protoplasm, constitute a classification of the most primitive forms of animal life. They are fantastically diverse, but three major groups may be identified on the basis of their motility. The Mastigophora have one or more long tails, which they use to project themselves forward. The Ciliata, which use the same basic means for locomotion as the Mastigophora, have a larger number of short tails. The Sarcodina, which include amoebae, float or row themselves about on their crusted bodies.
(2) In addition to their form of movement, several other features discriminate among the three groups of protozoans. For example, at least two nuclei per cell have been identified in the Ciliata, usually a large nucleus that regulates growth but decomposes during reproduction, and a smaller one that contains the genetic code necessary to generate the large nucleus.
(3) Protozoans are considered animals because, unlike pigmented plants to which some protozoans are otherwise almost identical, they do not live on simple organic compounds. Their cell demonstrates all of the major characteristics of the cells of higher animals.
(4) Many species of protozoans collect into colonies, physically connected to each other and responding uniformly to outside stimulae. Current research into this phenomenon, along with investigations carried out with advanced microscopes may necessitate a redefinition of what constitutes protozoans, even calling into question the basic premise that they have only one cell. Nevertheless, with the current data available, almost 40,000 species of protozoans have been identified. No doubt, as the technology improves our methods of observation, better models of classification will be proposed.
What is protoplasm?
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Đáp án B
(1) The protozoans, minute, aquatic creatures each of which consists of a single cell of protoplasm
CÂU HỎI HOT CÙNG CHỦ ĐỀ
Câu 1:
Mark the letter A, B, C, or D on your answer sheet to indicate sentence that is similar in meaning to the given one
"If I were you, I would take the job," said my room-mate.
Câu 2:
Mark the letter A, B, C, or D on your answer sheet to indicate sentence that best combines each pair of sentences in the following questions
We didn’t want to spend a lot of money. We stayed in a cheap hotel.
Câu 3:
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.
His ……………….. of the school regulations really can’t be ignored any longer.
Câu 4:
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.
Beaches were ……………….. as police searched for canisters of toxic waste from the damaged ship.
Câu 5:
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.
She wondered if they ……………………. her jeweler and rather hoped that they had.
Câu 6:
Mark the letter A, B, C or D on your answer sheet to indicate the word whose underlined part differs from the other three in pronunciation in each of the following questions.
Câu 7:
Mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the following questions.
He ……………………. alone a month ago, and …………………… of since.
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