Could you please help me express sentence 1. We have to consider the fact that groups of 10 students will be working on biodiversity in each school of the three schools separately and at the end they will compare their results.

1) Task organization and information distribution
The division of the various task will be ..... on the basis of the logical breakdown of the investigations
2) Experimental method
Students will be involved in the following investigating activities:
Systematic observation, measurement, and experiment
Formulation, testing, and modification of hypotheses

2 answers

You're not including ALL the steps of the scientific method. Students need to start from the beginning, not somewhere in the middle of the process:

1. Ask a Question
2. Do Background Research
3. Construct a Hypothesis
4. Test Your Hypothesis by Doing an Experiment
5. Analyze Your Data and Draw a Conclusion
6. Communicate Your Results
http://www.sciencebuddies.org/science-fair-projects/project_scientific_method.shtml

Read through this, too.
http://sciencefairproject.virtualave.net/scientific_method.htm
Who will come up with the questions from which all investigations will stem?
On sentence 1, it would be helpful instead of the word logical, put something more specific. As in, what criteria does logic take? I would change it to "systematic", at least that implies some structure.