Describe the biological chemical processes that were responsible for producing oxygen in Earth's atmosphere, eventually leading to the Cambrian Explosion. Explain the importance of oxygen in the evolution of large multicellular animal life.

Explain how organisms could be harmed by high levels of salt from roadways?

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.

This is an active transport mechanism by which cells pump sodium and potassium ions against the concentration gradient