To classify soil by type, soil scientists... a. measure the amount of humus.
b. measure the proportions of particles of different sizes.
c. measure the depth of the three soil horizons.
d. none of these.

What are charcteristics of lithosphere?

What is true of all organisms in the kingdoms protista, plantae, fungi, and animalia? a. they are multi-celled. b. they are photosynthetic. c. they have cells that contain membrane-bound organelles. d. they contain cells that lack membrane-bound organelles.

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?