2020 WAEC Biology Practical 3 Questions and Answers Solutions

100% VERIFIED BIOLOGY PRACTICAL ANSWERS

(1ai)
TABULATE:
-TEST: Specimen B + 2 drops of iodine solution
-OBSERVATION: No reaction is occurred
-INFERENCE: It indicates specimen B contains no starch content

(1aii)
TABULATE
-TEST: Specimen B + 2ml of NaOH(aq) + 3 drops of CuSO4 + shake
-OBSERVATION: The mixture will turn to purple or violet colour
-INFERENCE: Protein is present

(1b)
(i) Test for starch
(ii) Test for protein

(1c)
(i) They are source of food
(ii) They acts as antioxidants supporting the immune system

(1di)
Fungi

(1dii)
(i) Possession of hyphae
(ii) Absence of chlorophyll
(iii) Cell walls is made of chitin instead of cellulose

(1diii)
(i) Molds
(ii) Mildews
(iii) Smuts
(iv) Yeast

(1ei)
Mollusca

(1eii)
[Choose Any THREE]
(i) Possession of soft and unsegmented bodies
(ii) Body is covered by a mantle and shell
(iii) They are bilaterally symmetrical
(iv) They are triploblastic with three layers

(1fi)
Specimen C (mushrooms) are decomposers breaking down surface waste releasing nitrogen back into the soil in form of ammonium nitrate, a nutrient essential for plant survival

(1fii)
Saprophytic mode of nutrition
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(2a)
E – Berry
F – Berry
H – Dry Dehiscent Fruits

(2b)
E – Parietal placentation
F – Axile placentation

(2c)
E – Animals
F – Animals
H – Self dispersal

(2di)
Birds, squirrels, and other small mammals consumes the fruit which will lead to dispersal of the seeds in faeces or as they carry them from the tree to their habitats

(2dii)
(i) Vitamin such as vitamin C
(ii) Mineral such as Potassium, magnesium, iron

(2ei)
Green

(2eii)
It signifies that the pod is young and immature

(2fi)
Marginal placentation

(2fii)
Diagram

==========================

(4a)
Table


(4b)
The biological Phenomenon that occurred is Diffusion

(4ci)
– Stiring
– Heating

(4cii)
– Shaking
– Stiring

(4ciii)
– Size of medium
– Wind

(4di)
(View image)

(4dii)
Use either loops, whorls or arches

(diii)
Accidental, double loop, tented arch fingerprint

(4div)
(a) Its highly accurate
(b) Very useful in criminal identification
(c) It is easy to use
(d) It is unique and can never be the same for two people

(4dv)
Morphological variation
(4dii)
Use either loops, whorls or arches

(diii)
Accidental, double loop, tented arch fingerprint

(4div)
(i) Its highly accurate
(ii) Very useful in criminal identification
(iii) It is easy to use
(iv) It is unique and can never be the same for two people

(4dv)
Morphological variation

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