WAEC 2024 BIOLOGY ANSWER


BIOLOGY OBJ
1-10: CCBBBBABAC
11-20: CCABDBAADD
21-30: BDADDABABA
31-40: ACCAACBCCD
41-50: BCBCADCBCA


(1ai)
Glomerulus:
(PICK ANY ONE)
(i) It filters blood to form glomerular filtrate.
(ii) It removes waste products and excess substances from the bloodstream.
(iii) It initiates the urine formation process by allowing water and small molecules to pass through while retaining larger molecules like proteins.

(1aii)
Bowman's capsule:
(PICK ANY ONE)
(i) It collects the filtrate produced by the glomerulus.
(ii) It forms primary urine by capturing the filtrate and directing it into the nephron.
(iii) It serves as a funnel, guiding the filtrate into the proximal convoluted tubule for further processing.

(1aiii)
Proximal convoluted tubule:
(PICK ANY ONE)
(i) It reabsorbs water, ions, and nutrients from the filtrate back into the bloodstream.
(ii) It plays a crucial role in secreting waste products such as hydrogen ions and ammonia into the tubular fluid.
(iii) It maintains pH balance by selectively reabsorbing bicarbonate ions and secreting hydrogen ions.

(1aiv)
Distal convoluted tubule:
(PICK ANY ONE)
(i) It reabsorbs sodium and water, thus playing a key role in regulating blood pressure and fluid balance.
(ii) It secretes potassium and hydrogen ions, which helps in maintaining electrolyte and acid-base balance.
(iii) It also regulates calcium and phosphate levels in the blood, contributing to bone health and metabolic functions.

(1b)
|ORGANISM | Structure.. |..Form in which|

|Paramecium|Contractile vacuole|Liquid (water)

|Flatworm |Flame cells| Ammonia|

|Earthworm|Nephridia | Urea|

|Cockroach|Malpighian tubules|Uric acid|

|Human | Kidneys| Liquid(urine)|

|Plant | Stomatal pore| Gaseous (water vapor, oxygen, carbon dioxide

(1c)
(PICK ANY FIVE)
(i) Oxygen
(ii) Carbon dioxide
(iii) Water vapor
(iv) Resins
(v) gums
(vi) Latex
(vii) Tannins
(viii) Essential oils

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(2a)
(i) Mouth: Breaking down the cassava and groundnut soup into smaller particles through chewing (mechanical digestion)

(ii) Skin:
-Regulating body temperature through sweating to cool down the individual.

(iii) Tongue: Mixing food with saliva, aiding in taste and swallowing.

(iv) Kidney: Regulating water balance and blood pressure, since the individual did not drink water after the meal.

(v) Stomach: Mixing food with stomach acid and enzymes to break down proteins and carbohydrates.

(vi) Small intestine: Absorbing nutrients from the broken-down food into the bloodstream.

(vii) Large intestine: Absorbing water and electrolytes from the remaining waste material.

(viii) Liver: Detoxifying the blood, metabolizing nutrients, and regulating blood sugar levels.

(2b)
(i) Mouth (contains salivary amylase)
(ii) Stomach (contains pepsin and gastric amylase)
(iii) Small intestine (contains various enzymes like lactase, sucrase, and proteases)
(iv) Tongue (contains amylase)

(2c)
(PICK ANY THREE)
(i) Amylase
(ii) Pepsin
(iii) Lipase (breaks down fats into fatty acids and glycerol)
(iv) Lactase (breaks down lactose into glucose and galactose)
(v) Trypsin (breaks down proteins into peptides and amino acids)

(2d)
(PICK ANY TWO)
(i) Glucose
(ii) Amino acids
(iii) Fatty acids and glycerol
(iv) Vitamins and minerals

(2ei)
(PICK ONLY ONE)
(i) Dehydration (due to increased urine production)
(ii) Blood pressure increase (due to sodium's effect on blood vessels)
(iii) Stomach discomfort or pain (due to irritation of the stomach lining)

(2eii)
(PICKY ANY THREE)
(i) Energy provision (from carbohydrates, proteins, and fats)
(ii) Building and repair of tissues (from amino acids and other nutrients)
(iii) Maintenance of healthy gut bacteria (from fiber in cassava and groundnut soup)
(iv) Immune system support (from vitamins, minerals, and antioxidants)
(v) Satiety and satisfaction (from the meal's nutrient density and flavor)

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(3ai)
(i) The meat may turn dark brown or grey as it starts to spoil.
(ii) A strong, unpleasant smell of decay will likely develop due to bacterial decomposition.
(iii) The meat may become slimy and sticky as bacterial and enzymatic activities break down the tissues.
(iv) Visible mold or fungal growth may appear on the surface of the meat.

(3aii)
Decomposition

(3aiii)
(i) Refrigeration - Low Temperature
(ii) Salting - Dehydration and Osmosis
(iii) Smoking - Dehydration
(iv) Canning - Sterilization

(3aiv)
(PICK ANY TWO)
(i) Temperature (warmth)
(ii) Humidity (high moisture)
(iii) Oxygen (Presence of air)
(iv) Microorganisms (bacteria, fungi, etc.)

(3b)
(i) Dired maize grains: Storage in airtight containers or silos
(ii) Fresh tomatoes: Refrigeration
(iii) Veetables: Freezing
(iv) Beans: Canning
(v) Milk: Pasteurization

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(4ai)
| Cell | Type...| Set of.|
|-----------|--------|----------
|Onion cell | Mitosis| Diploid
|Sperm cell | Meiosis| Haploid
|Pollen grain| Meiosis| Haploid
|Ovum | Meiosis| Haploid
|Guard cell | Mitosis | Diploid
|Cheek cell | Mitosis | Diploid


(4aii)
(PICK ANY ONE)
Mitosis is the process of cell division wherein the chromosomes replicate and get equally distributed into two daughter cells.

OR

Mitosis is a process of cell division where a single cell divides into two identical daughter cells. It is crucial for growth, development, and tissue repair in organisms.

(4b)
(PICK ANY ONE)
Parents with blood groups A or B can have an offspring with blood group O if both parents carry one recessive allele for blood type O. When each parent passes on the O allele to their child, who receives one from each parent, the child's genotype would be OO, resulting in blood group O. This is possible due to the Mendelian inheritance pattern where the O allele is recessive to both A and B alleles.

OR

For parents with blood groups A or B to have an offspring with blood group O, both parents must carry at least one recessive O allele (i.e., genotype AO or BO). When these parents produce offspring, there is a chance that they can pass on their O allele to the child. If the child receives an O allele from each parent, they will have blood group O, as the O allele is recessive to both A and B alleles.

(4c)
(PICK ANY ONE)
Genes drive evolution by passing on hereditary traits across generations. Mutations create genetic diversity within populations, providing the raw material for natural selection to act upon. Natural selection favors advantageous traits, leading to evolutionary changes over time. Additionally, genetic drift and gene flow further shape the genetic makeup of populations, contributing to the diversity and adaptation of species.

OR

Genes are the units of heredity passed from parents to offspring. Through mutation, genetic variation arises, leading to diversity within populations. Natural selection acts on these variations, favoring traits that enhance survival and reproduction. Over time, advantageous traits become more common in a population, driving evolutionary change. Genes encode the traits that are subject to selection, shaping the adaptation and evolution of species.

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(5ai)
(PICK ANY ONE)
Competition is the process by which living organisms in a habitat struggle or compete with one another for limited essential needs such as food, light, nutrients, shelter or space in the environment.

OR

Competition is an interaction between organisms or species in which both the organisms or species are harmed. It arises when individuals or populations vie for the same resource (such as food, water, space, shelter, mate, ecological status, etc.) that is in limited supply.


(5aii)
(i) Intraspecific competition
(ii) Interspecific competition


(5aiii)
(PICK ANY FOUR)
(i) Food
(ii) Water
(iii) Shelter
(iv) Space
(v) Sunlight
(vi) Nutrients

(5aiv)
(PICK ANY ONE)
During succession, early pioneer species colonize an area with little competition due to harsh conditions. As the ecosystem matures, resources increase, leading to heightened competition among species. This competition drives the succession process, as more competitive species outcompete and replace earlier ones, resulting in a progressively more diverse and stable ecosystem over time.

OR

Competition and succession are linked in ecosystems. Early in succession, pioneer species face little competition. As ecosystems develop, resources increase, and competition among species intensifies. This drives succession, with more competitive species replacing earlier ones, leading to a stable and mature ecosystem.

(5bi)
(PICK ANY ONE)
Structural adaptation refers to physical features of an organism that enhance its ability to survive and reproduce in its specific environment. These adaptations involve the organism's body structure, such as shape, size, and special body parts, that help it to survive in its habitat.

OR

Structural adaptations refer to the changes in the structure of a living organism that enables it to adapt better to its environment. These adaptation consist of special body parts, such as skin, color, and shape.

(5bii)
(i) Camouflage
(ii) Mimicry
(iii) Body Coverings and parts
(iv) Specialized limbs and appendages

(5c)
(PICK ANY FOUR)
(i) Fingerprints
(ii) Facial Recognition
(iii) DNA Profiling
(iv) Retinal Scans
(v) Voice Recognition

(5d)
(PICK ANY THREE)
Adaptive coloration | Example
(i) Camouflage | Chameleon
(ii) Disruptive Coloration | Zebra
(iii) Warning Coloration | Poison dart frog
(iv) Mimicry | Viceroy Butterfly
(v) Countershading | Great White Shark

(5e)
(PICK ANY THREE)
(i) Rubber Tree
(ii) Pitcher Plants
(iii) Giant Water Lilies
(iv) Banana Trees
(v) Orchids
(vi) Bromeliads
(vii) Ferns

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