WAEC 2020 - PRACT BIOLOGY ANSWER

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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) Presence of tentacles
(ii) Possession of soft and unsegmented bodies
(iii) Body is covered by a mantle and shell
(iv) They are bilaterally symmetrical
(v) 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)
[Click here for the Image]

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(4ai)
TABULATE:
-TEST: 2 drops of specimen P in a Beaker of water, allowed to stand
-OBSERVATION TIME (seconds): A trail of it's purple colour goes to the bottom and diffuses in 605secs
-MEDIUM OF SPREAD: Liquid (slow diffusion)
-SENSE ORGAN: EYES

(4aii)
-TEST: A leveled spoonful of specimen Q in a beaker of water, stir
-OBSERVATION TIME (seconds):197 seconds
-MEDIUM OF SPREAD: Liquid (moderate diffusion)
-SENSE ORGAN: EYES

(4aiii)
-TEST: Specimen R cut open and notice the time odour was smelt
-OBSERVATION TIME (seconds): 2 Seconds
-MEDIUM OF SPREAD: Air (fast diffusion)
-SENSE ORGAN: Nose

(4b)
Diffusion of gases

(4ci)
(i) Stirring
(ii) Heating

(4cii)
(i) Shaking
(ii) Stirring

(4ciii)
(i) Size of medium
(ii) Wind

(4d)
PLACE YOUR THUMBPRINT IN UR PAPER PLS

(4dii)
PLS NAME YOUR PATTERN OF UR FINGERPRINT(SEE THE TYPES BELOW)

(4diii)
[Choose ANY THREE]
(i) Loop
(ii) Arch
(iii) Compound
(iv) Whorl

(4div)
(i) It is used in crime detection
(ii) It used as mark of identity
(iii) It serves as a means of security in technological devices

(4dv)
Morphological variation

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