In a previous IGCSE examination paper$^1$, the following question was asked and answer provided:
State one source of mineral particles in soil.
Accept any one of:
- down wash;
What's "down wash" and how is it responsible for providing minerals to soil? Googling the term lead me to an aerodynamics definition, which I doubt is the one referred to by the marking scheme.
$^1$ UCLES. Environmental Management, 0680/12, Paper 1. Cambridge International General Certificate of Secondary Education, February/March 2017.