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1. (1a)
   The classification of living things involves grouping organisms based on their characteristics. The current classification system consists of Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.

   (1bi)
   -Fungi-
   (i)Decomposition- Fungi decompose organic matter and recycle nutrients, contributing to soil health.
   (ii)Medicine- Some fungi are used in medicine, such as Penicillium, which produces antibiotics.
   (iii)Food- Edible mushrooms are a popular food item across the world. Certain fungi like yeast are used in baking and fermentation to produce wine and beer.
   (iv)Industry- Fungi are used in industries like paper manufacturing and in the production of enzymes like citric acid and gluconic acid.

   (1bii)
   -Plants-
   (i)Food- Plants are a major source of food for humans and animals.
   (ii)Oxygen production- Through photosynthesis, green plants produce oxygen which is essential to all living organisms.
   (iii)Raw materials- Fibers are obtained from plants and are used to make clothing, paper, and other products. Plants like timber and bamboo are used for construction purposes.
   (iv) Medicine- Many plants contain compounds with medicinal properties that are used in traditional medicine and pharmaceutical industry.

   (1c)
   (i) Cnidaria; Hydra
   (ii) Nematoda; Ascaris
   (iii) Chordata; Dog, cat
   (iv) Annelida ; Earthworm, leeches
   (v) Mullusca; Snail, slugs, limpets

   (3a) The types of relationships are:

   I: Decomposition or saprophytic relationship
   II: Commensalism
   III: Mutualism
   IV: Predation
   V: Parasitism

   3b) In relationship IV:
   – Organism B: Prey
   – Organism G: Predator

   3c) Examples of organisms B to J

   B: Dead tree
   C: Vulture
   D: Lion
   E: Hermit crab
   F: Sea anemone
   G: Snake
   H: Bee
   J: Sheep

   3d)
   (i) The relationship that is most beneficial to the ecosystem is III (Mutualism).

   (3dii) One reason for this is that mutualistic relationships involve interactions where both organisms benefit from each other’s presence, contributing to the overall stability and productivity of the ecosystem.

   3e)
   (I) Examples of organism A:
   – Fungi (such as mushrooms or molds) that grow on decaying matter
   – Bacteria that decompose organic material

   (3eii) The group to which organism A belongs is the decomposers or decomposer organisms.

   (2a)
   [FILL IN THE TABLE WITH THIS]

   IRON:
   Function:
   (PICK ANY ONE)
   -Chlorophyll formation
   -Electron transport in photosynthesis
   -Enzyme activation
   -Nitrogen fixation

   Effects of deficiency in plants:
   (PICK ANY ONE)
   -Chlorosis (yellowing of leaves)
   -Stunted growth
   -Reduced fruit and seed production
   -Interference with nutrient uptake

   MOLYBDENUM:
   Function:
   (PICK ANY ONE)
   -Nitrogen fixation
   -Enzymatic reactions
   -Iron uptake and utilization
   -Seed germination and growth
   -Chlorophyll formation

   Effects of deficiency in plants:
   (PICK ANY ONE)
   -Reduced nitrogen fixation
   -Chlorosis (yellowing of leaves)
   -Impaired sulfur metabolism
   -Abnormal phosphorus uptake
   -Altered enzyme activity

   POTASSIUM
   Function:
   (PICK ANY ONE)
   -Osmotic regulation
   -Enzyme activation
   -Protein synthesis

   Effects of deficiency in plants:
   (PICK ANY ONE)
   -Stunted growth.
   -Leaf chlorosis.
   -Weak stems.
   -Reduced flower and fruit production.
   -Increased susceptibility to diseases and pests.

   COPPER
   Function:
   (PICK ANY ONE)
   -It plays a vital role in activating various enzymes within plants
   -It helps to facilitate photosynthesis
   -It helps facilitate respiration in plants

   (PICK ANY ONE)
   Effects of deficiency in plants:
   -Stunted growth
   -Yellowing of leaves
   -Death of plant tissue
   -Reduced fertility
   -Increased susceptibility to diseases

   NITROGEN
   Function:
   (PICK ANY ONE)
   -It helps in building proteins
   -It is a fundamental constituent of nucleic acids and DNA
   -It helps in formation of chlorophyll
   -It helps in energy transfer and metabolism
   -It is an enzyme co-factor

   Effects of deficiency in plants:
   (PICK ANY ONE)
   -Reduced photosynthesis
   -Poor protein synthesis
   -Leaf necrosis
   -Increased susceptibility to diseases and pests.
   -Impaired nutrient transport

   (2b)
   (PICK ANY THREE)
   (i) Fruits and Vegetables
   (ii) Grains and Cereals
   (iii) Legumes and Pulses
   (iv) Nuts and Seeds
   (v) Dairy Products
   (vi) Meat, Poultry, and Fish

   (2ci)
   BUCCAL CAVITY:
   (PICK ANY TWO)
   (i) The buccal cavity is the entry point for food and liquids into the digestive system.
   (ii) The buccal cavity is responsible for chewing or masticating food.
   (iii) The buccal cavity contains salivary glands that produce saliva.
   (iv) The buccal cavity plays a vital role in speech production.

   (2cii)
   DUODENUM
   (PICK ANY TWO)
   (i) The duodenum receives partially digested food from the stomach and continues the process of digestion.
   (ii) The duodenum is involved in the absorption of nutrients from digested food.
   (iii) The duodenum plays a role in regulating the overall process of digestion.
   (iv) The duodenum secretes several important hormones that regulate various aspects of digestion.

   (2ciii)
   STOMACH
   (PICK ANY TWO)
   (i) One of the primary roles of the stomach is to store food temporarily after it has been ingested.
   (ii) The stomach aids in the mechanical digestion of food through muscular contractions known as peristalsis.
   (iii) The stomach secretes gastric juices, primarily composed of (HCl) and enzymes such as pepsin, which play a crucial role in chemical digestion.
   (iv) The stomach controls the rate at which food is released into the small intestine.

   (2d)
   Glucose and fructose
   [6/7, 12:13 PM] Donprosper: *BIOLOGY OBJ*
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   11-20:DBADDADBBC
   21-30:ADABDAADCD
   31-40:BDCBDCBBBA
   41-50:BBCCBCACDC

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2. SECTION A

   1. (a) The classification of living things, also known as taxonomy, is the science of organizing and categorizing organisms based on their similarities and evolutionary relationships. It involves grouping organisms into hierarchical categories, from broad to specific, based on their shared characteristics.

   [2 marks]

   (b) Economic importance of organisms in their habitats:

   (i) Fungi:
   1. Decomposers: Fungi play a crucial role in decomposing organic matter, breaking it down into simpler forms and recycling nutrients back into the ecosystem.
   2. Medicine: Some fungi produce bioactive compounds used in the production of antibiotics and other pharmaceutical drugs.
   3. Food: Certain edible fungi, such as mushrooms and truffles, are cultivated and consumed as food.
   4. Industrial applications: Fungi are used in various industries, such as brewing, baking, and cheese-making, where they contribute to the fermentation processes.

   (ii) Plants:
   1. Food production: Plants provide a significant portion of the world’s food supply, including grains, fruits, vegetables, and oils.
   2. Oxygen production: Through the process of photosynthesis, plants release oxygen into the atmosphere, which is essential for the survival of most organisms.
   3. Medicine: Many pharmaceutical drugs are derived from plants, and traditional medicine relies heavily on plant-based remedies.
   4. Economic resources: Plants serve as raw materials for numerous industries, such as timber, paper, textiles, and biofuels.

   [8 marks]

   *SECTION B*

   5a)
   Sense organ: A sense organ is an organ made up of a group of specialized cells/tissues/receptors , which is able to receive/collect/perceive/detect stimulus and transmit the information/impulse/message to the nervous system.

   5(a) Sense organs are specialized structures in the body of living organisms that enable them to perceive and respond to environmental stimuli.

   (5i)
   1. Nose: Responds to airborne chemical substances like aroma or odors.
   2. Taste buds: Detect chemicals present in food or solution to give the perception of taste.
   3. Olfactory epithelium: Receives and detects dissolved substances in the mouth and throat, giving a sense of smell.

   (5b)

   1. Male lions: Patrol and mark their territory with urine to protect their pride of females and young ones.
   2. Red squirrels: Territorial and have defined territories that they defend and mark using scent glands.
   3. Male gorillas: Beat their chests and charge at intruders who try to enter their territory.

   5(ii)

   1. Swans: Mate for life and form long-term pair bonds that they maintain.
   2. Seahorses: Form permanent pair bonds during breeding seasons and raise offspring together.
   3. Prairie voles: A species of rodent that forms lifelong bonds and engages in behaviors like grooming and huddling to maintain social bonding.

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