2018 WAEC Biology Practical Answers Expo/Runs
Below are WAEC Biology Practical Answers 2018
Question 1
LIST OF SPECIMENS PROVIDED
SPECIMEN A: GARDEN EGG
SPECIMEN B: TRIDAX FRUIT
SPECIMEN C: GRAIN WEEVIL
SPECIMEN D: TICK
SPECIMEN E: RAT/GUINEA PIG
SPECIMEN J: TILAPIA FISH (WET PRESERVED)
SPECIMEN K: TOAD (WET PRESERVED)
SPEICMEN L: LIZARD (WET OR DRY PRESERVED).
Question 1
Study carefully specimens A and B and use them to answer questions
1(a) to 1(c).
(i) Name the types of fruit in specimens A and B with reasons [ 4 marks ]
(ii) Make a drawing, 8 – 10 cm long of the lateral view of
Specimen B and label fully. [ 10 marks ]
Describe the modes of dispersal of specimens A and B. [ 6 marks ]
In a tabular form, state five differences between specimens A and B [ 5 marks ]
OBSERVATION: This was the less popular question in this section. Most candidates could not correctly name the type of fruits in specimens A and B. Some wrote that specimen A is a succulent, true fruit While specimen B is a dry indehiscent fruit. Some candidates who got the correct answer missed the mark because of wrong spellings. The expected answers were:
Specimen A/Garden egg is a Berry
Specimen B/Tridax fruit is a Cypsela.
They could not state the reasons correctly.
Expected answers include:
A/Berry- it has a fleshy pericarp with many seeds embedded in it.
B/Cypsela - fruit bears a hairy calyx/hairy pappus/parachute;
- dry single seeded fruit.
Most candidates performed fairly in the diagram of specimen B/Tridax but did not show the rachis of the pappus with double lines and did not conform to size specifications. This led to them scoring low marks. Only few candidates could correctly state the modes of dispersal of specimens A and B and correctly state five differences between the specimens. Expected answers include:
b)(i) Modes of dispersal
A/Garden Egg
The fruit is soft and edible;
Man and animals eat the soft pericarp;
The seeds are spat out /egested /scattered.
B/ Tridax
> Feathery papus traps air;
> This increases the surface area of the fruit with respect to the volume;
> So reduces the weight of the fruit;
> To be blown and dispersed by the wind;
> Tough (dry) pericarp protect the seed embryo.
Differences between specimens A and B
Specimen A(Garden Egg) Specimen B(Tridax Fruit)
Fleshy pericarp Dry pericarp;
Smooth epicarp/fruitwall Hairy epicarp;
No pappus Pappus present;
Calyx beneath fruit Calyx (pappus) on top of fruit;
Calyx present Calyx modified into pappus;
Large fruit Small fruit;
Heavy fruit Light (in weight) fruit;
Green/white/yellow in colour Brown in colour.
Question 2
Study carefully specimens E and F and use them to answer 2(a) to 2(d)
(i) What class of organisms do specimens E and F belong to? (1 mark)
(ii) State three similarities between specimens E and F (3 marks )
(Iii) In a tabular form, state three differences between specimens E and F (3 marks )
State two ways each in which:
(i)Specimen E;
(ii) Specimen F are of economic importance (4 marks )
OBSERVATION: This was the most popular in this section and a lot of candidates scored high marks in this question. Most candidates could correctly state the class to which specimens E/cockroach and F/soldier termite belong namely, class insect but a good number of candidates lost the score due to spelling errors e.g. class insecter instead of insect. The candidates could properly state similarities between the specimens, their economic importance; their habitats and their adaptations against predators. They however performed poorly in outlining the differences between specimens E and F. Expected answers include:
Specimen E/Cockroach Specimen F/Solder Termite.
Small head; Large head
Wings present; Wings absent
Has compound eye/has sigh; No eye/blind/no sight
Dark brown colour Light brown colour
Small mandibles present. Large mandibles present
A few candidates made good drawings of specimen E/cockroach and scored good marks but a large number of candidates mad poor diagrams with blunt pencils leading to wooly and broken lines. Some candidates failed to remove the wings of the cockroach and so lost marks. Many candidates did not give titles to their diagrams, did not state the magnification and had guidelines of labels crossing each other. In addition a lot of candidates loss marks due to poor spelling of labels.
Expected answers include:
Title(T) Drawing of dorsal view of specimen E (Cockroach) Quality (Q)
Size: 8 – 10cm (Sz)
Clarity of lines (CL) (lines not wooly x ½ ; not broken/dotted x ½ )
Neatness of labels (NL) (ruled guidelines x ½ ; horizontal labels x ½ )
Magnification (mg) x 1.5 – 2.5;
Details (D)
At least five abdominal segments shown (AS)/spiracles shown (SS)
Label(L)
Head, antenna, compound eye. Thoracic segment/prothorax, mesothorax and metathorax, spiracle, abdominal segment, leg (jointed) circus.
Question 3
Carefully study specimens J and K and answer questions 4(a) to 4(d).
Name the type of refuse in specimens:
(i) J;
(ii) K. (2 marks )
(i) List three animal vectors of disease causing organisms that breed on each of specimens J and K (6 marks)
(ii) Name four diseases each caused by the animal vectors associated with each of specimens J and K (8marks )
Name one method of disposal of each of specimens J and K in:
(i) Rural areas;
(ii) Urban areas. (4 marks )
(i) State four effects of improper disposal of specimen K (4 marks )
(ii) In a tabular form, state five differences between specimen J and K (5 marks )
(iii) Outline one way in which specimen J is of importance to farmers. (1 mark )
OBSERVATION: Many candidates performed fairly well on this question and scored fair marks. Most candidates could state the type of refuse namely J- dry refuse/waste and K wet refuse/waste/sewage/ Most candidates could correctly state animal vectors that breed on specimens J and K and the diseases associated with the specimens but lost marks due to spelling errors. Expected answers include:
Animal vectors that breed on specimen J
- Rat;
- Housefly;
- cockroach.
Animal vectors that breed on specimen K
- Housefly;
- Black fly;
- Female Aedes/Anopheles mosquito/mosquito;
Disease associated with specimen J
Typhoid; plague; dysemtery; cholera; diaorrhea.
Diseases associated with specimen K