(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;
- turbidity;
- temperature.
(c) Explain briefly the contributions of the following scientists to the formulation of the cell theory:
- Robert Hooke;
- Theodore Schwann.
(d) What is meant by each of the following terms:
- Nastism
- Taxism
(e) Make a diagram, 6 cm – 8 cm long of the human tongue illustrating the four areas of taste.
(f)(i) List four ways through which microorganisms enter the human body.
(ii) State three harmful effects of microorganisms to humans.
Explanation
(a) Processes involved in water cycle
- Respiration by plants/animals;
- Transpiration;
- Surface run-off/erosion;
- Excretion by plants/animals;
- Decay of plants/animals;
- Precipitation /rainfall;
- Condensation of water vapor/ cloud;
- Absorption of water by root hairs;
- Evaporation;
- Percolation;
- Perspiration/ sweating;
(b) Instruments for measuring the following physical factors
pH – pH meter/pH paper/ colorimeter;
Light intensity – light meter/photometer;
Turbidity – Secchi disc;
Temperature –thermometer.
(c) Contributions to cell theory
(i) Robert Hooke: He discovered the cell; while using a microscope to examine the cork from a tree bark; he observed honeycomb structures/dead cell walls surrounding empty holes; which he called ‘cells’.
(ii) Theodore Schwann: Examined bits of different animals under the microscope; and observed that all animals are composed of cells.
(d) (i) Nastism
Refers to the non-directional response of plant organs/part of a fixed plant to external /non-directional or diffused stimuli/touch/temperature/humidity/( e.g. leaves of Mimosa plant folding up when touched); it is not a growth movement; it is reversible (e.g. 4-0-clock flower).
(ii) Taxism
It is not a growth movement; directional response of motile/whole organisms; towards / away from to an external stimulus/ light/ chemicals/ temperature; (e.g. Euglena swimming away from chemicals; Euglena swimming towards light, etc.)
(e) Diagram of the human tongue showing areas of taste
(f) (i) Ways through which microbes enter the human body
- Through some parts of the body/Mouth; mucous membranes/mucosa; anus; skin; birth canal /vagina; nose;
- Insect bite;
- Blood contact;
- Direct contact with infected person/animal;
- Body secretions/semen/saliva/sweat/vaginal fluids/tears/mucus;
- Food;
- Water;
- Inhalation/aerosol.
(ii) Harmful effects of microbes to humans
- Causes various diseases in humans;
- Involved in spoilage of food;
- Causes death of humans;
- Destruction of materials/wood/cotton/leather/paper/any correctly named example.