Which element accounts for half of the dry weight of cells?

A cell is made up of the following elements, oxygen, hydrogen, nitrogen, carbon, phosphorus, magnesium, calcium, sodium, iron, potassium, etc. The dry weight of the cell will lack the water molecules. The element that will contribute to the maximum weight in the dry weight is Carbon. Carbon makes up the various proteins, carbohydrates, genetic material, cellular fibres, lipids, etc in the cell.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.