Empty protistan shells composed of pectin and containing an oily residue most likely once belonged to members of the phylum a. euglenophyta c. pseudopodia b. chrysophyta d. dinoflagella

The modern periodic table has groups.

There is a single path for electrons. the current decreases when additional resistors are added. the current will be the same in each resistor. these statements best describe a(n) circuit.

15. which of the following is not human-caused groundwater pollution? a. water in an aquifer dissolves elements such as arsenic and mercury from surrounding rock. b. water in an aquifer is contaminated by leachate that seeps into the ground from a landfill. c. water in an aquifer becomes polluted with chemicals used in hydraulic fracturing, or fracking. d. water in an aquifer absorbs harmful bacteria from the drainage field of a septic tank.