Banana peels can be used to purify drinking water contaminated with toxic heavy metals such as copper and lead, according to a study. Researchers from the Bioscience Institute at Botucatu, Brazil, said that the skins can outperform even conventional purifiers such as aluminium oxide, cellulose and silica. These have potentially toxic side effects and are expensive. The team's method follows previous work that showed that plant parts, such as apple and sugar cane wastes, coconut fibres and peanut shells, can remove toxins from water. These natural materials contain chemicals that have an affinity for metals. In the process, the researchers dried the peels in the sun for a week, ground them and added them to river water containing known concentration of copper and lead. They found that the peels absorbed 97 her cent of the metals after just one hour. The peels were tested in the lab and worked perfectly. Eventually their efficiently reduces, at which point the metals should be removed from the peels so that they can be disposed of safely. In addition, they said that although the peels were tested only on copper and lead, the material could also work on cadmium, nickel and zinc. But they warned that this sort of filter is better suited to industrial purposes and cannot be used for water purification at home as the extraction capacity of banana peels despends on the particle on the particle size of the heavy metals and this is difficult to measure. Dimitri Kalderis, from the Technical University of Crete, Greece, said: the results are very promising and the banana peel processes has proven to be a cost-effective and quick alternative to conventional methods. The knowledge is there, what we need now is innovation and construction. 10. What is the authors main purpose in writing the passage? A. To explain the reason for the need to use banana skins in daily life B. To classify the types of plant parts found useful as a water purifier C. To suggest that banana peel function can further be examined D. To describe how banana peels can remove toxins from water E. To demonstrate the existence of toxic elements in the water

Question

Jawaban yang benar adalah D. To describe how banana peels can remove toxins from water.

Soal menanyakan tujuan teks.

Pada teks terdapat kalimat "Banana peels can be used to purify drinking water contaminated with toxic heavy metals such as copper and lead, according to a study." yang artinya "Kulit pisang dapat digunakan untuk memurnikan air minum yang terkontaminasi logam berat beracun seperti tembaga dan timah, menurut sebuah penelitian."

Kemudian di paragraf selanjutnya terdapat kalimat "In the process, the researchers dried the peels in the sun for a week, ground them and added them to river water containing known concentration of copper and lead." yang artinya "Dalam prosesnya, para peneliti mengeringkan kulitnya di bawah sinar matahari selama seminggu, menggilingnya dan menambahkannya ke air sungai yang mengandung konsentrasi tembaga dan timbal yang diketahui."

Berdasarkan penggalan dua gagasan utama teks di atas, maka dapat disimpulkan bahwa tujuan dari teks adalah untuk menggambarkan bagaimana kulit pisang dapat menghilangkan racun dari air.

Jadi, jawaban yang benar adalah D. To describe how banana peels can remove toxins from water.

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