Plant propagation 60 plant layering 59 plant harvesting 58 Sociology 32 metabolism 19 Crop improvement 16 Currency 14 Trade Union 14 Wage Act 14 Cytology 13 photosynthesis 13 Economics 12 Engineering 12 Expenditure 12 Income tax 12 Plant Breeding 12 Public debt 12 Taxation 12 morphology 12 Plant cell 11 Social stratification 11 personal saving 11 Genetics 10 Nucleus 10 Plant physiology 10 Viral chromosomes 10 unconscious mental forces 10 Cell Division 9 Finance 9 Physiological psychology 9