Which of the following best describes topsoil? a. topsoil is made entirely of decomposed organic remains. b. topsoil is made of humus and clay minerals washed down from the layer above the topsoil. c. topsoil is made of humus and mineral particles weathered from the soil's parent material. d. topsoil is made entirely of minerals weathered from the underlying parent material.

The answer is C.

Topsoil is made of humus and mineral particles weathered from the soil's parent material.

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o