Observation

 

This question was compulsory.

Question 5(a), a few candidates could list the structures that make up the dermis of the human skin, although some could not spell correctly.
In 5(b), some candidates could not state the similarities between the process of decay and digestion.
In 5(c), some candidates could explain the ways by which plants and animals are interdependent.
In 5(d), many candidates could not list the examples of density-dependent and
density-independent factors in ecology.
In 5(e), candidates could not state the behavioural adaptations of honeybees satisfactorily but could state the beneficial effect of bees in pollination and production of honey.
In 5(f), some candidates could state ways by which animals survive unfavourable conditions.
In 5(g), candidates could state some functions of Public Health Authority.

 

The expected answers are:

(a) Structures that make up the dermis of the human skin

 

• Nerve endings/touch receptors/pain receptors/ cold receptors/heat receptors/thermoreceptors/nerve endings;
• Sweat duct;
• Erector muscle
• Sweat gland;
• Adipose tissue;
• Blood capillaries;
• Hair papilla/hair root;
• Sebaceous gland;
• Hair follicle;
• Connective tissues.                                                                                  

Note: Spellings must be correct to score.                                                                                   

 

(b)    Similarities between the process of decay and digestion

 

• Both act on organic substances;
• Both involve use of enzymes;
• Both involve breakdown of larger molecules into smaller/simple molecules;
• Both involve the use of energy;
• Both involve the release of heat;
• Both use water;
• Both are extracellular.                                                              

 

 (c)       Ways by which plants and animals are interdependent in a forest habitat

 

• Green plants/producers manufacture food;
• Animals/consumers feed on manufactured food/producers;
• Plants provide shade/shelter for animals;
• Animals produce carbon dioxide;
• Which plants use for photosynthesis;
• Plants produce oxygen which animals use for respiration;
• Animals release wastes that plants utilize;
• Dead bodies of animals release nutrients to the soil for plant use;
• Pollination of plant flowers by animals;
• Animals help in dispersal of fruits/seeds of plants;
• Some plants are used as medicine by animals.                            

 

(d)      Example of:
(i) density-dependent factors as used in ecology

 

• disease;
• competition;
• pollution;
• predation;
• food supply;
• space/overcrowding;
• migration/emigration/immigration;
• mortality;
• natality.                

Note: Spellings must be correct to score.  

 

(ii) density-independent factors as used in ecology

• floods;
• end of breeding season;
• adverse weather;
• earthquake;
• fire;
• adaptation.

Note: Spellings must be correct to score.    

 

(e) (i)  Behavioural adaptations of honeybees

 

• visual stimuli/use of sunlight; for direction to locate source of food/hive;
• secretion of chemical scents/substances/pheromones; to recognise/remember/trail members of the family/colony back to the hive;
• worker bees make body contacts; that enable to trail the direction of food from the source to their hive/to share food among themselves;
• perform waggle dance; to sensitize other bees on the location of the food/richness/distance of the food.                                                                                   

(ii)  Beneficial effects of bees to humans

 

• production of honey;
• production of wax;
• agent of pollination.                                                                     

(f)  Ways by which animals survive unfavourable conditions

 

• hibernation;
• aestivation;
• formation of spores/sporulation;
• formation of capsule/encapsulation;
• migration.                                                                                     

 

  (g) Functions of a public health authority

 

• ensures cleanliness of public places/markets/schools/playgrounds/food industries;
• concerned with the proper disposal of refuse;
• provides maternity clinics/health centres/nursing homes/family planning;
• provides child welfare services;
• provides medical inspection of schools;
• registers birth/death;
• prevents/controls infectious diseases/administers vaccination/immunization/inoculation;
• informs World Health Organization of the outbreak of infectious diseases;
• ensures adequate provision of clean water to the public;
• provides ambulance services;
• provides quarantine services for plants/animals/humans;
• gives health certificate to travellers;
• provides public health education/awareness of diseases;
• inspects and certifies health of animals and cleanliness of slaughter house/abattoir;
• inspection and certification of imported food/medicine before release to markets.