Microplastics, referring to plastic fragments and particles (碎片和微粒) less than 5 millimeters in diameter (直径), have been found on Mount Qomolangma as high as 8,440 meters above sea level, just 408.86 meters below the peak of the mountain, according to a recent study published in the journal One Earth. Scientists collected snow and water samples from 19 different     1     (spot). They found microplastics in all the water samples and part of the snow samples. The most     2     (pollute) sample was from the Base Camp in Nepal,     3    most human activity on the mountain is concentrated. It had 79 particles of microplastics per liter (升) of snow.