Which systems work together to deliver oxygen to the cells of the body?

Which of these statements are true about scientific theories and hypothesis

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.

Which of the following is a true statement? question 8 options: populations can't evolve, only individual organisms. individuals have adaptations that can change over time. individuals have traits that may or may not make them successful at reproduction. individuals evolve to have adaptations.