Waec gce biology answers 2021

Here is the waec gce biology answers for 2021.

Biology-Obj-
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(1a)

(i) Spiders senses through their cuticles while insects possesses one pair of antenna

(ii) The body of spiders is divided into two segments: cephalothorax and abdomen, whereas the body of insects is divided into three segments: head, thorax, and abdomen.

(iii) Spiders have eight legs while insects have six pairs of legs

(iv) Spiders have four appendages while insects have three

(1bi)

[Tabulate]

PRAWN:

(i) It has ten legs

(ii) Has two body segments

(iii) Absence of wings

(iv) Possession of rostrum

(v) Absence of stylus

COCKROACH:

(i) It has six legs

(ii) Has three body segments

(iii) Possession of wings

(iv) Absence of rostrum

(v) Presence of stylus

(1bii)

(i) Both has compound eyes

(ii) Both posseses antenna

(iii) Both has abdomen

(1c)

(i) Possession of detachable tail for safety when it needs to escape from the predator

(ii) Possession of sharp, tricuspid teeth that help catch, grab, grip, and cut prey

(iii) Possession of four legs and has powerful limb for escape

(iv) Possession of fringe-toe which enables them move quickly across the sand.

4bi A chromosome is a structure found inside the nucleus of a cell. A chromosome is made up of proteins and DNA organized into genes. Each cell normally contains 23 pairs of chromosomes.

4bii. Functions of chromosome

i. The most important function of chromosomes is to carry the basic genetic material – DNA. DNA provides genetic information for various cellular functions. These functions are essential for growth, survival, and reproduction of the organisms.

ii. Histones and other proteins cover the Chromosomes. These proteins protect it from chemical (e.g., enzymes) and physical forces. Thus, chromosomes also perform the function of protecting the genetic material (DNA) from damage during the process of cell division.

iii. During cell division, spindle fibers attached to the centromeres contract and perform an important function. The contraction of centromeres of chromosomes ensures precise distribution of DNA (genetic material) to the daughter nuclei.

(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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