Humus is dark colored organic material in soil; it is left over from the decay of living things.
true or false?

Any sound above what db can cause hearing loss in human beings

The activity of the modern sample is 1.10 bq . how long does that measurement take?

What are the two causes of density in deep current waters? a. salinity (how much salt) of the water and high temperaturesb. salinity (how much salt) of the water and low temperatures c. oxygen content of the water and high temperatures. d. oxygen content of the water and low temperatures