(a) State five processes involved in the water cycle. (b) Name one instrument used for measuring each of the following physical factors: pH; light intensity...

(a) Five processes involved in the water cycle

1. Evaporation (of water from seas, rivers and land).
2. Transpiration (loss of water vapour from plants).
3. Condensation (water vapour forming clouds).
4. Precipitation (rain, hail or snow).
5. Run-off (and infiltration into the ground).

(b) Instruments for measuring each physical factor

(c) Contributions to the cell theory

• Robert Hooke: using an early microscope he examined thin slices of cork and observed and named the tiny box-like compartments \'cells\', the first observation of cells.
• Theodore Schwann: he proposed that all animals are made of cells and, with Schleiden, stated that all living things are composed of cells, so the cell is the basic unit of life.

(d) Meaning of terms

• Nastism (nastic movement): a non-directional response of a plant part to a diffuse (non-directional) stimulus, for example the folding of Mimosa leaves when touched.
• Taxism (taxis): the movement of a whole organism towards or away from a directional stimulus, for example a Euglena swimming towards light.

(e) A diagram 6 to 8 cm long of the human tongue is required, showing and labelling the four taste areas: sweet (tip), salt (front sides), sour (back sides) and bitter (back of the tongue).

(f)(i) Four ways microorganisms enter the human body

1. Through the mouth in contaminated food and water.
2. Through the nose in inhaled air (droplets).
3. Through cuts, wounds or breaks in the skin.
4. Through the reproductive tract (sexual contact) or insect bites.

(f)(ii) Three harmful effects of microorganisms to humans

1. They cause diseases such as cholera, tuberculosis and malaria.
2. They cause food spoilage and food poisoning.
3. They produce toxins that poison the body and cause decay of body tissues (sepsis).