The theory that a drug attaches itself to specialized cells in the body because of it's size, shape, electrical charge, and chemical properties is called 1) pharmacological attachment theory 2) drug physiology 3) drug interaction theory 4) receptor site theory ?

Which statement describes both homogeneous mixtures and heterogeneous mixtures?

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.

Why is the bottom layer of a trophic pyrimid the