Please help Identify the variables in this hypothesis.

If Sam increases his exposure to excessive noise by listening to music through his headphones, then his ability to hear will decrease. This is because when sounds are too loud, they can damage sensitive structures in the inner ear and cause hearing loss.

The independent variable is

.

The dependent variable is

.

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.