Why is it important for scientists to share information from their investigation?

So that such information can be analysed, scrutinised and verified with the use of experiments. Good scientists are naturally sceptical about the information that they produce. They strive to produce reliable and testable theories (using the information they have at their disposal) which can be used to find cures for diseases and also to develop the technology of the future.

The independent variable would be the fertilizer as it is what the dependent variable (the growth of grass) depends on.