2021 WAEC MAY/JUNE BIOLOGY PRACTICAL Questions & Answers: 2020 WAEC MAY/JUNE BIOLOGY PRACTICAL ANSWERS Night before Exam

Monday, 31st August 2020
Biology 3 (Practical) (Alternative A) – 09:30 a.m. – 11:30a.m. (1st Set)
Biology 3 (Practical) (Alternative A) – 12:00 p.m – 2:00 p.m. (2nd Set)

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==COMPLETED==

(1ai)

TABULATE

- TEST: Specimen B + 2drops of iodine solution

- OBSERVATION: No precipitate is found (No reaction is occurring)

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 (Biurets test)

(1c)
- Additional income is obtained through quality mushrooms
- They contain vitamins and proteins and Laos acts as antioxidants supporting the immune system

(1di)
Fungi

(1dii)
- Eukaryotic organism
- Absence of chlorophyll
- Cell walls made of chitin instead of cellulose

(1diii)
- Moulds
- Mildews
- Smuts
- Rusts
- Yeast

(1ei)
Mollusca

(1eii)
- Presence of tentacles
- Possession of soft and unsegmented bodies
- The body is covered by a mantle and she'll
- They are bilaterally symmetrical
- 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

(2ei)
Green

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

(2fi)
Marginal placentation

(2fii)

(4a)
TABULATE
- Specimen P-
- Test: 2 drops of specimen P in water
- Observation time(seconds): 3-4 seconds before it dissolves
- Medium of spread: Water
- Sense organ: Eye

-Specimen Q-
- Test: Teaspoon of specimen Q + water
- Observation time(seconds): Dissolves within 65 seconds
- The medium of spread: Water
- Sense organ: Eye

-Specimen R-
- Test: Cut section of specimen R
- Observation time(seconds): 2 seconds or almost immediately
- The medium of spread: Air
- Sense organ: Nose

(4b)
Osmosis

(4c)
(i)
- Increase in temperature
- Difference in concentration
(ii)
- Molecular size
- Increase in temperature
(iii)
- Increase in temperature
- Difference in concentration

(4di)

(4dii)
It is Whorl

(4diii)
- Loop
- Whorl
- Arch/Compound

(4div)
- Crime detections
- Identification of individuals
- Genetic variation in man

(4dv)
Discontinuous variation

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