Which type of barrier are coughing and sneezing? mechanical chemical biological physical

Two students are working together on an experiment that measures the effect of different liquid fertilizers on the thickness of plants’ stems. which is most likely to result in the greatest amount of error in their scientific experiment? a.one student measures the plant stem widths by using calipers. the other student measures the widths of the same plant stems again by using a different pair of calipers. b.one student measures the plant stem widths by using calipers. the other student types the measurements as they are taken into a computer spreadsheet. c.one student weighs liquids for the experiment by using a calibrated scale. the other student weighs liquids for the experiment by using a different calibrated scale.

Ascientist wanted to formulate a pill to attack a specific type of bacteria that infects the throat. which biological component would be best to use as a model for the pill's function? bacteriocytes phagocytes complement antibodies

The united states uses which source of energy to produce almost 40 percent of its electricity