2022 Waec Chemistry Expo

2021 WAEC Gce biology Question And Answers [Expo/Essay/Objectives] Now Available

2021 WAEC Gce biology Question And Answers [Expo/Essay/Objectives] Now Available

WAEC Gce biology Expo Answers 2021: Hello Dear, welcome to Expocoded, your best WAEC 2021 exam help desk. It’s just a few hours before the exam.

Welcome to the WAEC Gce biology Objective & Essay Answers to Questions for the years 2021.

2021 WAEC Gce biology Question And Answers

*WAEC GCE BIOLOGY*

 

(1a)

(i) Insects fall under the class Insecta while spiders fall under the Arachnida class

(ii) A spider’s head and thorax are fused while their abdomen is not segmented

(iii) Spiders also do not have distinct wings or antennae like insects.

(iv) A spider is not an insect because insects have 6 legs two, compound eyes, three body parts and spiders have have eight legs with only two body parts.

 

(1bi)

TABULATE

 

-PRAWN-

(i)A prawn have up to 10 legs.

(ii) The prawn will usually grow to 5 inches in length.

(iii) A prawn have rostrum for defence

(iv) A prawn have pleopod for swimming

(v) They don’t have wings

 

-COCKROACH-

(i) An average cockroach have only 6

(ii) Cockroaches are mostly 2 inches at their longest

(iii) Cockroaches don’t have this extra feature

(iv) Cockroaches don’t have pleopod

(v) Cockroaches have wings

 

(1bii)

(i) The cockroach and the prawn have exoskeletons that It manifests as a thick outer shell that gives their bodies structure.

(ii) The cockroach and prawn have multiple legs that look spiky

(iii) The cockroach and prawn have similar antennas and segmented abdomen

 

(1c)

(i) Metachromatism helps lizards accomplish the regulation of internal temperature.

(ii) Thermoregulation which involves behavioral adaptations that negate the desert environment.

(iii) Lizards use burrows, or underground holes, as a means of adapting to the desert heat.

(iv) The fringe-toed lizard have scales which enable the lizard to move quickly across sand, providing traction in the desert environment.

 

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(2a)

Photosynthesis can be tested by testing for starch in a green leaf. The leaf is detached after about 2-3 hours in the sun, boiled and then the green pigment is extracted using alcohol. Iodine solution is then added to the leaf. It turns blue-black, it shows photosynthesis has taken place.

 

(2bi)

(i) Oxygen

(ii) Carbon dioxide

 

(2bii)

(i) Oxygen : Water in leaf

(ii) Carbon dioxide: Atmosphere

 

(2ci)

This is because they do not have teeth and they can not chew solid particles

 

(2cii)

(i) Minerals

(ii) Vitamin

(iii) Protein

(iv) Carbohydrate

 

(2d)

Add some of the egg white to the biurets solution in the test tube and mix thoroughly while still hand warming. The blue colour will change to violet to show the presence of protein

 

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(4a)

The process takes place in three main steps which are: initiation, elongation and termination. In order to fit within a cell’s nucleus, DNA is packed into tightly coiled structures called chromatin, which loosens prior to replication allowing the cell replication machinery to access the DNA strands. The later leads to the replication of the gene.

 

(4bi)

It houses the gene

 

(4bii)

(i) X-chromosome

(ii) Y-chromosome

 

(4c)

This is because the process of cell division takes place. During this process, meiosis occurs leading to the production of haploid number of chromosomes (n) from a diploid number

 

(4d)

[img]https://i.imgur.com/Oj1Il2N.jpg[/img]

 

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(5a)

Chemosynthesis is a process through which certain bacteria synthesize their food using inorganic materials in the soil. It is form of autotrophs nutrition eg Nitrification

 

(5b)

(i) Sunlight

(ii) Carbohydrate

 

(5c)

(i) Photosynthetic/holophytic

(ii) Carnivorous

 

(5d)

(i)Maize, rice

(ii)Sundew, dodder’s plant

 

(5e)

(i) It conduct and transmit the sensation of odour

(ii) Anterior end if cerebrum

(iii) Nose

(iv)They are both sense organs and they both transmit impulse in form of fluid. They are both connected via epiglottitis. They both transmit their impulse to the brain.

 

(5f)

(i) This can be defined as a behaviour that results in mating and eventual reproduction in animals. It is a form of display throwing readiness for mating

 

(ii) In domestic fowl, the female spread their feathers whenever a female shortly making undue noise which shows readiness for mating

 

(5g)

(i) Possession of bigger body which enables them to cater for the caste

(ii) Possession of sting to fight against predator

(iii) Possession of Wings for flight

 

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