Theme

VD

N (%)

D

N (%)

E

N (%)

VE

N (%)

Ecosystem

3 (5.9%)

2 (3.9%)

7 (13.7%)

39 (76.5%)

Nutrition

2 (3.9%)

8 (15.7%)

18 (35.3%)

23 (45.1%)

Acid and base

5 (9.8%)

6 (11.8%)

21 (41.2%)

19 (37.3%)

Electricity and magnetism

8 (24.2%)

12 (36.3%)

8 (24.2%)

5 (15.2%)

Force and motion

21 (63.6%)

5 (15.1%)

4 (12.1%)

3 (5.9%)

Heat

15 (45.5%)

8 (24.2%)

8 (24.2%)

2 (3.9%)