2 A1 ― Living things: their characteristics
3 A2 ― Cells: building blocks of life
4 A3 一 Cells, tissues, organs and organ systems
5 A4 一 Organs in plants 一 roots, stems, leaves and flowers
6 A5 ― Diffusion, osmosis and active transport
7 A6 一 Human digestive system
8 A7 ― Digestive processes
9 A8 - Blood and the human circulatory system
10 A9 一 Respiration
11 A10 - Breathing, gaseous exchange and respiration
12 A11 - The senses
13 A12 - The human eye
14 A13 - The nervous system
15 A14 - The endocrine system
16 A15 - Hormones and sexual reproduction
17 A16 - Homeostasis 1 ： controlling body temperature
18 A17 - Homeostsis 2: controlling water content
19 A18 - The body’s defence systems
20 A19 - Substance abuse
21 A20 ― Photosynthesis
22 A21 一 Water uptake and transpiration in plants
23 A22 一 Mineral requirements of plants
24 A23 - Hormones and plant growth
25 A24 一 Chromosomes, genes and cell division
26 A25 一 Variation and mutation
27 A26 一 Genes and inherited characteristics
28 A27 一 X and Y chromosomes
29 A28 一 Sexual and asexual reproduction
30 A29 一 Selective breeding and genetic engineering
31 A30 一 Variation, natural selection and evolution
32 A31 一 Evolution: the evidence
33 A32 ― Habitats, communities and populations
34 A33 一 Impact of humans on the environment
35 A34 一 Food chains and ecological pyramids
36 a35 一 Energy flow in ecosystems
37 A36 一 Managing food production
38 a37 一 The nitrogen cycle
39 A38 一 The carbon cycle
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