1. Genetics
   1. Characteristics
      1. Environmental?
         1. Hair Length
      2. Genetic?
         1. Eye Colour
         2. Hair Colour
         3. Nose Shape
         4. Ear Shape
         5. Skin Colour
      3. Both?
         1. Intelligence
         2. Height
         3. Feet Size
         4. Body Mass
   2. Genes
      1. Double Helix
      2. Bases
         1. A & T
         2. G & C
2. Drugs
   1. Classification
      1. A
      2. B
      3. C
   2. Type
      1. Depressant
      2. Painkiller
      3. Hallucinogen
      4. Stimulant
3. Pathogens
   1. Bacteria
      1. Bacteria are microscopic organisms that come in many shapes and sizes. But even the largest ones are only 10 micrometres long - 1 micrometre = 1 millionth of a metre.
   2. Virus
      1. Viruses are many times smaller than bacteria. They consist of a fragment of genetic material inside a protective protein coat.
   3. Fungi
      1. Larger fungi include moulds and mushrooms. Microscopic fungi can cause diseases such as athlete’s foot.
   4. Protozoa
      1. Some are parasites
      2. Protozoa are single-celled organisms. Food contaminated with protozoa can cause infections such as amoebic dysentery, of which severe diarrhoea is a symptom. Some protozoa are parasites. These organisms live on, or inside, another organism and cause it harm. Malaria is a disease caused by protozoa that live in the blood. It is passed to a person by an insect vector, the mosquito.