Câu hỏi:
13/03/2020 3,307Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 34 to 40.
An air pollutant is defined as a compound added directly or indirectly by humans to the atmosphere in such quantities as to affect humans, animals, vegetation, or materials adversely. Air pollution requires a very flexible definition that permits continuous change. When the first air pollution laws were established in England in the fourteenth century, air pollutants were limited to compounds that could be seen or smelled - a far cry from the extensive list of harmful substances known today. As technology has developed and knowledge of the health aspects of various chemicals has increased, the list of air pollutants has lengthened. In the future, even water vapor might be considered an air pollutant under certain conditions.
Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles. These serve as an air purification scheme by allowing the compounds to move from the air to the water or soil. On a global basis, nature's output of these compounds dwarfs that resulting from human activities. However, human production usually occurs in a localized area, such as a city. In such a region, human output may be dominant and may temporarily overload the natural purification scheme of the cycles. The result is an increased concentration of noxious chemicals in the air. The concentrations at which the adverse effects appear will be greater than the concentrations that the pollutants would have in the absence of human activities. The actual concentration need not be large for a substance to be a pollutant; in fact, the numerical value tells us little until we know how much of an increase this represents over the concentration that would occur naturally in the area. For example, sulfur dioxide has detectable health effects at 0.08 parts per million (ppm), which is about 400 times its natural level. Carbon monoxide, however, has a natural level of 0.1 ppm and is not usually a pollutant until its level reaches about 15 ppm.
For which of the following reasons can natural pollutants play an important role in controlling air pollution?
Sách mới 2k7: 30 đề đánh giá năng lực DHQG Hà Nội, Tp. Hồ Chí Minh, BKHN 2025 mới nhất (600 trang - chỉ từ 160k).
Quảng cáo
Trả lời:
A
Lý do nào dưới đây khiến chất gây ô nhiễm tự nhiên có thể đóng vai trò quan trong trong việc kiểm soát ô nhiễm không khí?
A. Chúng đóng vai trong là một phần của quá trình thanh lọc
B. Chúng chiếm số lượng lớn hơn những chất ô nhiễm
C. Chúng ít có hại với vật thể sống hơn các chất ô nhiễm khác
D. Chúng đã tồn tại từ khi trái đất phát triển
Dẫn chứng: Many of the more important air pollutants, such as sulfur oxides, carbon monoxide, and nitrogen oxides, are found in nature. As the Earth developed, the concentration of these pollutants was altered by various chemical reactions; they became components in biogeochemical cycles.
Tạm dịch: Nhiều chất gây ô nhiễm không khí quan trọng hơn, chẳng hạn như oxit lưu huỳnh, carbon monoxide và nitơ oxit, được tìm thấy trong tự nhiên. Khi Trái đất phát triển, nồng độ của các chất ô nhiễm này bị thay đổi bởi các phản ứng hóa học khác nhau; chúng trở thành các thành phần trong các chu trình hóa sinh
=> Đáp án: A
Đã bán 152
Đã bán 114
Đã bán 132
Đã bán 47
CÂU HỎI HOT CÙNG CHỦ ĐỀ
Câu 1:
Mark the letter A, B, C, or D on your answer sheet to indicate the most suitable response to complete each of the following exchanges.
“Would you like to have dinner with me?” – “______________.”
Câu 2:
Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
It is not always easy to make a good ______ at the last minute.
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.
A survey was _____ to study the effects of smoking on young adults.
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.
Mr.Brown has kindly agreed to spare us some of his _____ time to answer our questions.
Câu 5:
Mark the letter A, B, C, or D on your answer sheet to indicate the sentence that best combines each pair of sentences in the following questions.
A waitress served us. She was very impolite and impatient.
Câu 6:
Mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the following questions.
Do you know the boy ______ at the party last week?
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.
The exercises which we are doing ______ very difficult.
về câu hỏi!