The purpose of this experiment is to assess the effect of caffeine on the development of sea urchins. The gametes of sea urchins were collected and added to different concentrations of caffeine. The rate of development was measured by the fraction of eggs fertilized and cleaved under a microscope over the span of 40 minutes at intervals of 10, 25, and 40 minutes. Results show that sea urchins treated with 0.25 mg of caffeine have faster development than the control. On the other hand, sea urchins treated with 0.5 mg of caffeine have slower development than the control. These results indicate that small amounts of caffeine increase the rate of development, however, excessive amounts of caffeine lower the rate of development.
Comments
What is "excessive" is there
What is "excessive" is there a number or a range of the amount of caffine that would have a lower rate of development?
Be specific
"The gametes of sea urchins were collected and added to different concentrations of caffeine."
I think it would be helpful to just list the different concentrations, like 0 mg, 0.25 mg, etc for clarity.
comment
The time in this experiment is not controlled. It would reflect the development better if the intervals of time were consistent.