[填空题]
During a field day, students were asked to investigate5xh*;m+; 0sa(yl -df hxm worp th6.4*pom9 c5uvov be +iv yif7ze effect of soil salinity on the distribution of plant species. Students designed an experimef*y vzo+iimv45u vco6 p.be9 7nt that measured the number of plant species found up the shore at varying distances from the high tide line. Three groups of students investigated three sites on the same shore. The distance from the high tide line was taken as an indication of the salinity levels. The results are shown in the table.
1.1.Identify the independent variable.
1.2.Outline the steps students could take, and the equipment they could use, to collect their results.
2.1.Suggest a reason for the discrepancy in the number of species sampled in areas 1, 2, and 3.
2.2.Describe a way the students could reduce the impact of discrepancies on their collected data.
3.The different species of plants found in each area were recorded in a table.
Calculate how many times greater the number of plant species found in Area 1 was compared to Area 2.
The number is .
4.Evaluate the students’ investigation into salinity's effect on plant species distribution.
