Câu hỏi: Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer for each of the questions from 30 to 34.
Calcite-containing dust particles blow into the air and combine with nitric acid in polluted air from factories to form an entirely new particle-calcium nitrate. These nitrates have optical and chemical properties that are completely different from those of the originally dry dust particle. Due to this, climate models need to be updated to reflect this chemistry. Calcite dust is common in arid areas such as Israel, where this past winter scientists collected particles for analysis.
Working from a mountaintop, the team collected dust that had blown in from the northern shores of Egy pt, Sinai, and southern Israel. The particles had combined with air containing pollutants that came from Cairo. They analyzed nearly 2,000 individual particles and observed the physical and chemical changes at the w. R. Wiley Environmental Molecular Sciences Laboratory.
An important change in the properties of the newly formed nitrate particles is that they absorb water and retain moisture. These wet particles can scatter and absorb sunlight-presenting climate modelers, who need to know where the energy is going, a new wild card to deal with. Other studies of dust samples from the Sahara and the Saudi Arabian coast and from China show that the higher the calcium in the mineral, the more reactive they are with nitric acid. In fact, once the particle is changed, it stays that way.
In the scientists' research, where did the pollutants come from originally?
A. Arid areas
B. The Saudi Coast
C. Cairo
D. The Sahara desert
Calcite-containing dust particles blow into the air and combine with nitric acid in polluted air from factories to form an entirely new particle-calcium nitrate. These nitrates have optical and chemical properties that are completely different from those of the originally dry dust particle. Due to this, climate models need to be updated to reflect this chemistry. Calcite dust is common in arid areas such as Israel, where this past winter scientists collected particles for analysis.
Working from a mountaintop, the team collected dust that had blown in from the northern shores of Egy pt, Sinai, and southern Israel. The particles had combined with air containing pollutants that came from Cairo. They analyzed nearly 2,000 individual particles and observed the physical and chemical changes at the w. R. Wiley Environmental Molecular Sciences Laboratory.
An important change in the properties of the newly formed nitrate particles is that they absorb water and retain moisture. These wet particles can scatter and absorb sunlight-presenting climate modelers, who need to know where the energy is going, a new wild card to deal with. Other studies of dust samples from the Sahara and the Saudi Arabian coast and from China show that the higher the calcium in the mineral, the more reactive they are with nitric acid. In fact, once the particle is changed, it stays that way.
In the scientists' research, where did the pollutants come from originally?
A. Arid areas
B. The Saudi Coast
C. Cairo
D. The Sahara desert
Câu trả lời này dựa vào thông tin "...with air containing pollutants that came from Cairo"
Đáp án C.