| Animals and mammals | 8 mentions | P1, P2, P3, P4, P6, P7, P11, P12 |
| Dinosaurs | 7 mentions | P1, P2, P5, P6, P7, P8, P10 |
| Life on other planets | 6 mentions | P3, P4, P8, P9, P11, P12 |
| Chemical composition of Earth | 6 mentions | P1, P2, P5, P9, P8, P10 |
| Astronomy | 5 mentions | P3, P4, P5, P7, P9 |