WAEC GCE 2024 BIOLOGY PRACTICAL ANSWER


(1)



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(2ai)
A: Monocotyledonae
B: Dicotyledonae

(2aii)
A: Stem
B: Root

(2aiii)
I: Epidermis
II: Cortex
III: Endodermis
IV: Pericycle
V: Xylem
VI: Phloem
VII: Pith
VIII: Epidermis
IX: Cortex
X: Central vascular bundle

(2b)
(i) Protection: V
(ii) Transport of food: II
(iii) Transport of water and mineral salts: III
(iv) Absorbing of water from soil: VIII
(v) Support: VII

(2c)
IV: Large surface area, thin walls for efficient absorption.
VIII: Root hairs increase surface area, thin cell walls for water absorption.

(2d)
(i)A has a circular arrangement of vascular bundles, while B has a scattered arrangement.
(ii)A shows distinct vascular bundles, B does not.
(iii)A has a defined outer layer (epidermis), B shows a less defined boundary.
(iv)A is a typical dicot stem cross-section, B resembles a monocot root cross-section.

(2e)
(i) Transport of food: Translocation
(ii) Transport of water and mineral salts: Transpiration
(iii) Absorption of water from soil: Osmosis

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(3)


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WAEC GCE 2024 BIOLOGY THEORY AND OBJ ANSWER


WAEC GCE BIOLOGY
1-10: ADCDCCBDCD
11-20: CCCBCDDABA
21-30: BADADBDDAC
31-40: ABCCCBCCCA
41-50: DCDABCDDBA


(1)


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(2a)
The faces of lizards are more solid than those of mammals because lizards have a different skull structure. Lizards have a solid, bony skull with fused bones, whereas mammals have a more flexible skull with movable bones. This is because lizards do not need to chew their food as much as mammals do, so they do not require the same level of jaw mobility.

(2b)
(i)Saliva (produced by the salivary glands)
(ii)Gastric juice (produced by the stomach)
(iii)Pancreatic juice (produced by the pancreas)
(iv)Bile (produced by the liver and stored in the gallbladder)
(v)Intestinal juice (produced by the small intestine)

(2c)
(i)Pepsin (stomach) and pepsinogen (pancreas)
(ii)Gastric amylase (stomach) and pancreatic amylase (pancreas)
(iii)Trypsin (stomach) and trypsinogen (pancreas)

(2di)
(i)Both are biological molecules: Hormones and enzymes are both made up of proteins or other biological molecules.
(ii)Both have specific functions: Hormones and enzymes both have specific roles to play in the body, such as regulating metabolism or digesting food.
(iii)Both are highly specific: Hormones and enzymes are both highly specific in their actions, with each one targeting a specific cell, tissue, or biochemical reaction.

(2dii)
TABULATE!
(i)Hormones are produced and secreted by endocrine glands, such as the pancreas, thyroid, and adrenal glands. Enzymes are produced and secreted by various cells and tissues throughout the body.
(ii)Hormones bind to specific receptors on target cells, triggering a response. Enzymes, on the other hand, bind to specific substrates, converting them into products.
(iii)Hormones can be proteins steroids, or amino acids. Enzymes are typically proteins.

(2e)
(i) Glucose: 1 molecule
(ii) Water: 6 molecules
(iii) Oxygen: 6 molecules

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(3ai)
Ecology is the study of the relationships between living organisms and their environment. It examines how living things interact with each other and with the non-living components of their environment, such as air, water, and soil.

(3aii)
An ecosystem is a community of living organisms (plants, animals, and microorganisms) interacting with each other and with their physical environment. The components of an ecosystem are interdependent and form a complex web of relationships.

(3aiii)
The biosphere is the part of the Earth's environment that supports life. It includes all the living organisms on the planet, as well as the physical environment they inhabit, such as the atmosphere, hydrosphere, and lithosphere.

(3bi)
(PICK ANY TWO)
(i) Producers
(ii) Consumers
(iii) Decomposers
(iv) Abiotic factors

(3bii)
(PICK ANY TWO)
(i) Producers: Organisms that can synthesize their own food, usually through photosynthesis, and form the base of the food chain.
(ii) Consumers: Organisms that obtain energy by consuming other organisms, either directly (herbivores) or indirectly (carnivores and omnivores).
(iii) Decomposers: Organisms that break down dead organic matter, releasing nutrients back into the environment for reuse by producers.
(iv) Abiotic factors: The physical and chemical components of the environment, such as water, air, soil, and sunlight, which provide the necessary resources and conditions for life.

(3ci)
(PICK ANY FOUR)
(i) High species diversity
(ii) Lush vegetation and dense canopy
(iii) Warm and humid climate year-round
(iv) High rainfall (typically over 2,000 mm per year)
(v) Nutrient-poor soil
(vi) Vertical stratification of the vegetation

(3cii)
(PICK ANY TWO)
(i) Tall, straight trunks to reach the canopy and compete for sunlight
(ii) Broad, flat leaves to maximize light absorption for photosynthesis
(iii) Buttress roots to provide stability in the shallow, nutrient-poor soil
(iv) Ability to shed leaves during the dry season to conserve water
(v) Bark that is resistant to fire and pests
(vi) Seed dispersal mechanisms

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(4ai)
Organic evolution refers to the process by which species of living organisms change over time through variations in traits, inheritance, and natural selection. It is the gradual development of new species from common ancestors through genetic changes and adaptation to their environment.

(4aii)
(i) Fossil Record
(ii) Comparative Anatomy
(iii) Embryology
(iv) Molecular Biology
(v) Biogeography

(4bi)
The Theory of Use and Disuse suggests that body parts or organs that are used frequently become stronger and more developed, while those that are not used may diminish or disappear over generations. The idea is that environmental demands lead to the development or reduction of certain features based on their utility

(4bii)
Jean-Baptiste Lamarck.

(4biii)
(i) Giraffes
(ii) Aquatic organisms (like amphibians and their legs)

(4c)
Mutation refers to a sudden, random change in the genetic material (DNA) of an organism. Mutations introduce new genetic variations in a population. Some mutations are beneficial, giving organisms a survival advantage and thus increasing the likelihood of passing on these traits to future generations. Over time, these beneficial mutations accumulate and contribute to the evolution of new species

(4d)
(i) Aestivation: Lizard
(ii) Basking: Bat
(iii) Territoriality: Monkey
(iv) Hibernation: Polar bear

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(5a)
(i) Kills the protoplasm of the leaf and stops all enzyme activities in the cells.
(ii) To extract the chlorophyll from the leaf.
(iii) To distribute equal heat uniformly in the leaf.
(iv) To soften the tissues.

(5bi)
Courtship behaviour in animals consists of instinctive behaviours in response to certain external stimuli.

(5bii)
(i) Pairing
(ii) Display
(iii) Territoriality

(5ci)
TABULATE

NASTIC:
(i) Direction of the movement is independent of the direction of the stimulus
(ii) Movement shown by part of a plant

TASTIC:
(i) Movement is oriented towards the direction of the stimulus
(ii) Movement of whole organisms/entire plant

(5cii)
(i) Nastic movement ? Morning glory, Mimosa
(ii) Tactic movement ? Volvox, Chlamydomonas

(5di)
(i) Compatibility of blood of donors and recipients.
(ii) For identification.

(5dii)
TABULATE

DNA:
(i) Sugar of DNA has no oxygen.
(ii) The pyrimidines of DNA consist of thymine and cytosine.
(iii) Double-stranded molecules

RNA:
(i) Sugar of RNA contains oxygen.
(ii) The pyrimidines of RNA are made of uracil and cytosine.
(iii) Single-stranded molecules

(5ei)
A coleoptile is a protective sheath covering the emerging shoot in monocotyledonous plants such as maize.

(5eii)
Removing the coleoptile exposes the vulnerable plumule to damage from physical factors (e.g., abrasion, desiccation) and prevents the plant from effectively responding to light cues for optimal growth direction. This leads to retarded growth.

(5fi)
Haemophilia is rare in females because they need two copies of the mutated gene to express the condition, while males need only one.

(5fii)
A male child of a haemophilic father and a normal mother cannot be haemophilic because he inherits a Y chromosome from his father and a normal X chromosome from his mother