Observation

Many candidates attempted this question and performance was average.
Some candidates could not interpret that a food chain should start with the producer, in this case, the mango tree but they started with the hawk or the caterpillars. Hence, loss of marks occurred due to the wrong arrangement of organisms in the food chain, some candidates did not indicate the direction of flow with arrows or even used a wrong direction of arrows.

Some candidates did not write the title for the pyramid of numbers; some gave wrong arrangement of organisms; some mixed up the number of organisms provided; some drew a triangle instead of a pyramid; some candidates did not put the mango tree at the base of the pyramid; some did not indicate the number of organisms but just wrote the number. All these avoidable errors made candidates lose marks.

Some candidates answered 3 (b) quite well while some could not.

The expected answers are:

(a) (i) Food chain      
                

Correct arrangement of organisms                                                                           
Arrows (with arrow head) shown in correct direction                                         

(ii) Pyramid of numbers

Title (TL) Pyramid of numbers                                              
Correct arrangement of organisms (CA)                               
Number of organisms shown (NS)                                        
Shape of Pyramid (SP)                                                          

(b)      Benefits of conserving the following resources
(i) Water

• Required by all organisms for life/existence;
• Used for irrigation/agricultural purposes;
• Domestic purposes/sewage disposal;
• Industrial purposes;
• For reproduction in bryophytes/aquatic organisms/frog;
• Used to transport goods/good source of transportation;
• Serves as a tourist/recreational centre;
• To preserve biodiversity;
• Serves as habitat/place to live for organisms;
• Regulates climate/water cycle
• Used to generate electricity
• Universal solvent.                                                                  

(ii) Soil

• For farming activities;
• Serves as habitat/place to live/dwelling place for organisms;
• Supports forest/wildlife resources;
• Provides continuous source of plant nutrients/preserve soil fertility;
• Source of water for soil organisms;
• Source of raw materials for industries (chalk/coal/petroleum).

                                                                                                     
(iii) Forest

• For the generation of income/employment;
• For preservation of biodiversity;
• Home/habitat for some organisms/wildlife;
• Source of raw materials for industries (timber/paper, wood pulp);
• Centre of recreation/tourism;
• Source of food to human/animals;
• Source of firewood/coal/energy;
• For medicinal purposes
• Acts as wind breakers;
• Prevents soil erosion/desertification;
• Encourages rainfall/climate change;
• For aesthetic value/research.