(b) Mike and Rajiv plan an investigation to find out how running speed affects breathing rate. (i) Name the equipment they must use to measure their breathing rate.
[1]
(i) State one variable they need to change.
[11
(ili) State one variable they need to keep the same.
[1]
(iv) Suggest one way they record and present their results.
[11

You are given an electron micrograph of a bacterial cell. in the micrograph you can clearly see three thin layers of different densities surrounding the cell. based on the micrograph, you can infer that this cell is and would appear after application of the gram stain procedure. gram-negative / pink gram-positive / purple gram-positive / pink gram-negative / purple