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No expanded working has been attached for this question yet. The verified answer is Option A.

No expanded working has been attached for this question yet. The verified answer is Option C.

No expanded working has been attached for this question yet. The verified answer is Option A.

No expanded working has been attached for this question yet. The verified answer is Option C.

Plants primarily take in carbon dioxide (CO\(_2\)) through tiny pores called stomata located on the surface of their leaves. These pores, which are typically found on the underside of leaves, allow for the exchange of gases, including the entry of CO\(_2\) for photosynthesis and the release of oxygen. The opening and closing of stomata are regulated by specialized cells called guard cells, which help control water loss and gas exchange. Once CO\(_2\) enters the leaf through the stomata, it is used, along with water and sunlight, in the process of photosynthesis to produce sugars (food) for the plant. CO\(_2\) taken in by plants through their leaves via stomata is used in photosynthesis to create sugars, which are then transported to other parts of the plant for growth and energy.

Ovaries play a critical role in both menstruation and conception. They produce eggs for fertilization and they make the hormones estrogen and progesterone.

No expanded working has been attached for this question yet. The verified answer is Option B.

The interaction between P. aurelia and P. caudatum is interspecific competition, specifically demonstrating competitive exclusion. In this scenario, P. aurelia outcompetes P. caudatum for resources, leading to a decline in the P. caudatum population while the P. aurelia population continues to grow. This is because P. aurelia is more efficient at obtaining food, demonstrating that two species cannot occupy the same ecological niche indefinitely.

From the diagram,we can infer that P aurelia is better adapted for obtaining food than P caudatum because as number of days increases the number of P aurelia increases in number as well while P caudatum decreases with increase in the number of days. This implies that P aurelia tend to adapt more despite the competition because instead of decreasing in number, they were increasing in number progressively.

(a)(I)Types of fruits: Garden Egg/A-Berry. Reason: It has a fleshy pericarp with many seeds embedded in it. Tridax B-Cypsela. Reason: Fruit bears a hairy calyx/hairy pappus/parachute. Dry single seeded fruit. (c) Specimen A (Garden Egg) Specimen B (Tridax frut) Fleshy pericarp Dry pericarp Smooth epicarp/fruit wall Hairy epicarp No pappus Pappus present Calyx beneath fruit Calyx (pappus) on top of fruit Calyx present Calyx modified into pappus Large fruit Small fruit Heavy fruit Light (in weight) fruit Green/white/yellow in colour Brown in colour

From the diagram,we can infer that P aurelia is better adapted for obtaining food than P caudatum because as number of days increases the number of P aurelia increases in number as well while P caudatum decreases with increase in the number of days. This implies that P aurelia tend to adapt more despite the competition because instead of decreasing in number, they were increasing in number progressively.

(a) Factors affecting the rate of diffusion: - Presence of concentration gradient; when concentration of substance is high the rate of movement of molecules will increase/molecules move from the region of higher concentration to the region of lower concentration; leading to an increase in the rate of diffusion. Surface area: Large surface area will allow more molecules of substance to diffuse. State/nature of the diffusing substance: Molecules in gaseous state diffuse faster than those in liquids or solid states/molecules in solid state diffuse slower than those of liquid and gas. Size of the molecules/particles: The smaller molecules will move/diffuse faster than larger molecules. Temperature: Increase in temperature increases the movement of molecules/increases in diffusion/decrease in temperature slows down movement of molecules/decreases diffusion. (b)(i) Active transport: This is the movement of molecules from a region of low concentration to a region of high concentration/against a concentration gradient. Across a living membrane. Using energy from the cell. (ii) Transpiration: Loss of water in the form of vapour; from the aerial parts of plants. (c) Reduction of Transpiration: Closure of stomata during the day. Reduction of leaf size/leaf modified into spines. Dropping of leaves in the dry season. Development of thick cuticle. Presence of hairs over leave surfaces. Presence of sunken stomata. (d) Red Blood Cells: Biconcave shape/disc-like, increases its surface area for oxygen uptake. Elastic membrane, enables it to flow easily through the blood vessels. Presence of hemoglobin; for oxygen uptake. Thin membrane; for easy diffusion of oxygen/carbon-dioxide.

(a) Role of the stomach in digestion: The stomach receives food when the sphincter at the entrance of the stomach relaxes. The muscular walls of the stomach contract and relax, to churn/mix the food, and further break down the particles. The stomach produces gastric juices, which contain dilute hydrochloric acid/pepsin/rennin. The dilute hydrochloric acid neutralizes the action of the salivary amylase, and kills bacteria present in the food. It creates a suitable condition/pH for the action of pepsin, and activates inactive pepsinogen to form pepsin. The pepsin breaks down the protein to polypeptide/peptides. While the rennin coagulates/curdles milk to enhance digestion by pepsin. The mucus produced by the stomach wall lines the wall of the stomach to prevent the action of the acid on the stomach wall. The mucus produced by the stomach lubricates the movement of the food in the alimentary canal. (b)(i) Parts of plants where food is stored: Leaves. Stems. Roots. Seed. Fruits. (ii) Examples: Leaves: Onions, shallot, garlic. Stems: Yam, sugarcane, ginger, Irish potatoes. Roots: Cassava, carrots, sweet potatoes. Seed: Groundnut, beans, coconut, cashew. Fruits: Maize, guava, orange, pawpaw, cashew, palm nut, mango. (c) Sugar regulation in mammals: The liver controls the blood glucose levels. It converts excess glucose in the blood to glycogen. The process is stimulated by the hormone insulin, which is secreted by the pancreas. When the blood glucose level falls below normal. The pancreas secretes/glucagons. This stimulates the conversion of glycogen into glucose, which is released into the blood.

(a) Conservation: Conservation is the protection/preservation/restoration, and wise management/use of natural resources. Planning and management of resources from loss/waste/harm in order to achieve continuous use/ Sustainable quality of living for mankind OR Conservation is the wise/judicious/intelligent use of our natural resources to ensure their availability, and preserve the quality of the environment. (ii) Endangered species: Are organisms that have become depleted/rare. Due to human activity/natural disaster/epidemic. Those habitats have become so disturbed. That they may be lost forever/become extinct. (b)(i) Necessity to conserve forests: Economic importance: Forests produce timber for the construction industry/buildings/furniture/boats/paper. Domestic: Firewood for charcoal, medicines, gum/resins/rubber/tannins/chemicals/turpentine. Biological importance: Provide food/ shelter for many animals, reduce wind erosion/desertification, serves as wind breaks/checking strong winds, cause precipitation of water from damp air/can increase amount of rainfall in an area, protect source of streams/rivers, help in maintaining CO\(_2\) / O\(_2\) balance in the atmosphere/the plants remove CO\(_2\) for photosynthesis/supply 0\(_2\) /purifies the atmosphere. Educational: For ecological studies, to prevent certain species from getting extinct. Recreational/ Tourism: Serve as tourist attraction. (ii) Methods for the conservation of forests: Regulations made to control excessive deforestation, only mature trees should be felled. Planting new forest trees/afforestation where they have been completely destroyed. Discouraging extensive use of natural forests as a source of timber since animals and some other plants are also destroyed/displaced. Replacing harvested/felled mature trees by seedlings in plantations! reforestation. Prevention of forest fires. Controlling plant diseases by using pesticides/chemicals to kill pests. Using trained forest rangers/guards to guard the forests against intruders/fight fires. Educating the local population on the dangers of deforestation/carrying out awareness campaigns against deforestation. Establishment of forest reserve. (c)(i) Importance of decomposers in the ecosystem: They break down organic materials that are difficult for organisms to digest, they return organic matter to the environment in an inorganic form, so that they can be re-assimilated by plants/recycling nutrients. (ii) Plant decomposers: Fungi, Rhizopus, Bacteria. Animal decomposers: Earthworms, Termites.

(a)(i) What is a gene? Genes are units of heredity located in the chromosomes which are responsible for the coding of a particular protein to transfer trait or character from parents to offspring. (ii) Differentiate between the terms genotype and phenotype: Genotype is the genetic make-up of genes in an organism that is independent of the environment while a phenotype is all observable features, appearance of the organism that is determined by the environment and the genotype. (b) Explain the following terms: (i) Hybrid: Offspring produced from a cross between two parents with contrasting characters. (ii) Pure-breeding: A process of producing a particular genotype over many generations. (iii) Nucleotides: The basic building block of a nucleic acid consisting of a ribose, deoxyribose. protein, a phosphate group and a nitrogen base. (c) In a garden, pea seeds, smooth seed coat is dominant over rough feed coat. With the aid of a genetic diagram, determine the result expected if a homozygous rough pea is crossed with a smooth seed coat plant whose parents were rough coated.