I believe the answer is C) sand, gravel, and silt particles
Angola 1975-2002 (27 years)
Liberia 1998-2003 (14 years)
D.R Cong 1997-1999 (2 years)
Ethipo 1974-1991 (17 years)
True, they burn up in the mesosphere
Scale is very important with regards to human geography and population because it can interpret geographical information for certain reasons. For instance, if you analyze a geographical information from too small a scale, you could miss out important information that are apparent at smaller scales.