(a) With the aid of annotated diagrams only, outline the water cycle.
(b) Describe an experiment to show that water is conducted in the xylem tissue of flowering plants.
Explanation
(a) Water cycle
- Condensation in clouds
- Precipitation/Rainfall
- Evaporation of water from water bodies/river/sea/ ocean
- Evaporation of water from soil/ground
- Excretion by animals
- Drinking of water by animals
- Perspiration/sweating/respiration by animals
- Erosion/run-off of water from soil/ground
- Decay in plants/ animals.
(b) Experiment:
-A young herbaceous plant/balsam/water leaf/ plant is uprooted/cut a twig of a young herbaceous plant under water
- the cut twig/the roots are washed with water; to remove the soil particles
-a solution of a dye/eosin/red ink is made in a beaker
- the roots of the plant/cut twig is immersed in the solution.
- and set up exposed to sunlight
-and allowed to stand for one to six hours
-remove the plant from the solution and wash the roots/stem/of twig thoroughly
- make transverse sections of the root/stem
- observe the sections under the microscope
- it will be observed that only the xylem tissues pick the dye/is stained re-indicating that water is conducted in the xylem tissues.