2024 WAEC BIOLOGY ANSWERS
BIOLOGY OBJ
01-10: CCCBBBADAC
11-20: ACCBBDAADC
21-30: DCADDABDDA
31-40: ACCAACACCD
41-50: BBCAADCBBB
COMPLETED
(1a)
(i) Glomerulus:
The glomerulus filters blood to form a filtrate, which includes water, ions, and small molecules like glucose and amino acids, while retaining larger molecules such as proteins and cells.
(ii) Bowman’s Capsule:
The Bowman’s capsule collects the filtrate produced by the glomerulus and funnels it into the proximal convoluted tubule.
(iii) Proximal convoluted tubule:
The proximal convoluted tubule reabsorbs essential substances such as glucose, amino acids, and ions (e.g., sodium and chloride) from the filtrate back into the blood.
(iv) Distal convoluted tubule:
The distal convoluted tubule fine-tunes the reabsorption of ions and water, and it secretes additional waste products into the filtrate, helping to regulate electrolyte balance and pH.
(1b)
TABULATE
=ORGANISM=
(i) Flatworms
(ii) Earthworm
(iii) Cockroach
(iv) Human
(v) Plant
=STRUCTURE FOR EXCRETION=
(i) Flame cells
(ii) Nephridia
(iii) Malpighian tubules
(iv) Kidneys
(v) Stomatal pore
=FORM IN WHICH WASTE IS EXCRETED BY ORGANISM=
(i) Ammonia
(ii) Urea
(iii) Uric acid
(iv) Liquid (urine)
(v) Oxygen, carbon dioxide, and water vapor
(1c)
(i) Oxygen
(ii) Carbon dioxide
(iii) Water vapor
(iv) Resins
(v) Gums
(2a)
(i) Mouth;
The mouth is responsible for the initial mechanical breakdown of food through chewing and the enzymatic breakdown of starches through the action of saliva.
(ii) Skin;
The skin regulates body temperature through the process of sweating, which also helps to excrete excess salts and maintain homeostasis.
(iii) Tongue;
The tongue assists in the manipulation of food for chewing and swallowing, and contains taste buds that help in the sensory evaluation of food.
(iv) Kidney;
The kidneys filter blood to remove waste products and excess substances, producing urine, which helps to maintain the body’s fluid and electrolyte balance.
(v) Stomach;
The stomach produces gastric juices, including hydrochloric acid and digestive enzymes, which help in the breakdown of food into a semi-liquid form called chyme.
(vi) Small Intestine;
The small intestine is the primary site for nutrient absorption; it continues the process of digestion with the help of enzymes and bile, and absorbs nutrients into the bloodstream.
(vii) Large Intestine;
The large intestine absorbs water and salts from the material that has not been digested as food, and compacts the remaining material into feces for excretion.
(viii) Liver;
The liver produces bile, which aids in the digestion and absorption of fats, and processes nutrients absorbed from the small intestine, detoxifying harmful substances and storing nutrients.
(2b)
(i) Mouth (salivary glands produce amylase)
(ii) Stomach (produces pepsin)
(iii) Small intestine (produces various enzymes such as maltase, lactase, and sucrase; receives enzymes from the pancreas)
(2c)
(i) Amylase (in saliva) – Breaks down starches into sugars.
(ii) Pepsin (in stomach) – Breaks down proteins into peptides.
(iii) Lipase (from pancreas) – Breaks down fats into fatty acids and glycerol.
(2d)
(i) Glucose (from the breakdown of carbohydrates)
(ii) Amino acids (from the breakdown of proteins)
(2ei)
Excess salt can lead to increased blood pressure due to the retention of water, which increases the volume of blood.
(2eii)
(i) Energy – Carbohydrates in cassava provide a source of energy.
(ii) Protein – Groundnut soup contains proteins necessary for body repair and growth.
(iii) Nutrients – The meal provides essential vitamins and minerals required for overall health.
NUMBER FIVE
(5ai) Competition refers to the struggle between organisms for limited resources such as food, water, mates, or territory.
(5aii)
(I) Intraspecific competition: Competition occurring between members of the same species.
(II) Interspecific competition: Competition occurring between individuals of different species.
(5aiii)
(PICK FOUR)
(I) Food
(II) Water
(III) Shelter
(IV) Territory
(V) Mates
(VI) Light (for photosynthesis in plants)
(5aiv) Competition influences succession by shaping the composition and abundance of species in an ecosystem. Intense competition among species in the early stages of succession can lead to the dominance of certain species, while others may be excluded. As succession progresses and environmental conditions change, the intensity and outcomes of competition may also change, affecting the trajectory of succession.
(5bi) Structural adaptation refers to physical features or characteristics that enhance an organism’s survival in its environment.
(5bii)
(PICK FOUR)
(i) Camouflage
(ii) Mimicry
(iii) Protective coloration
(iv) Structural modifications (e.g., wings, claws, teeth)
(v) Body shape (e.g., streamlined bodies for aquatic animals)
(vi) Specialized appendages (e.g., long necks in giraffes)
(5c)
(PICK FOUR)
(i) DNA fingerprints
(ii) Facial features
(iii) Hair characteristics
(iv) Blood type
(v) Skin color
(vi) Iris patterns
(5e) An example of a plant found in the tropical rainforest is the orchid.