what type of symbiosis do certain bacteria live in human intestines, where they get food and help humans break down their food.

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.

Scientists have developed an explanation of a phenomenon from several verified hypotheses. the explanation has been confirmed through numerous experimental tests.which option best describes this explanation? a. scientific lawb. research questionc. hypothesisd. scientific theory

If two identical atoms are bonded,what kind of molecule is formed