Compare and contrast organic and inorganic compounds, and define gestation, heat, and parturition periods in ruminants. Explain recessive traits.

b) Comparison of organic and inorganic compounds:

• Melting point: Organic compounds generally have lower melting points, while inorganic compounds generally have higher melting points.
• Boiling point: Organic compounds generally have lower boiling points, while inorganic compounds generally have higher boiling points.
• Solubility in water: Organic compounds are generally less soluble in water (more soluble in organic solvents), while inorganic compounds are generally more soluble in water.
• Conductivity: Organic compounds are generally poor conductors of electricity, while many inorganic compounds (especially ionic ones) are good conductors when molten or in solution.
• Biodegradability: Many organic compounds are biodegradable, while inorganic compounds are generally non-biodegradable.

c) Explanation of terms in ruminants:

• Gestation period: This is the period of time during which a mammal carries an embryo or fetus inside its uterus, from conception to birth.
• Heat period (or estrus): This is the period when a female mammal is fertile and receptive to mating, often characterized by behavioral changes.
• Parturition: This is the act or process of giving birth to offspring in mammals.

d)

i) A recessive trait is a genetic trait that is only expressed when an individual inherits two copies of the recessive allele (one from each parent). It is masked when a dominant allele is present.

ii) Genotypes:

• (a) A sickle cell carrier: $\boxed{\mathbf{Hb^A Hb^S}}$ (where $Hb^A$ is the normal allele and $Hb^S$ is the sickle cell allele).
• (b) A person with Blood Group B: $\boxed{\mathbf{I^B I^B}}$ or $\boxed{\mathbf{I^B i}}$

4.

a)

i) Groups to which the compounds belong:

• W: Alcohol
• X: Carboxylic acid
• Z: Ester

ii) One acid that can be represented by Y is sulfuric acid ($\text{H}_2\text{SO}_4$).

iii) The function of Y (the acid) in this reaction is as a catalyst. It speeds up the reaction without being consumed.

b) Five causes of mortality during brooding of day-old chicks are:

• Starvation/Dehydration: Chicks fail to find food or water.
• Chilling/Overheating: Improper brooding temperature.
• Diseases: Such as Coccidiosis, Marek's disease, or bacterial infections.
• Predation: By rodents, cats, or other animals.
• Poor ventilation: Leading to accumulation of harmful gases like ammonia.

c)

i) Decomposers are organisms that break down dead organic matter (dead plants, animals, and waste products) into simpler inorganic substances, returning nutrients to the soil and atmosphere.

ii) Four examples of decomposers in a forest ecosystem are:

• Bacteria
• Fungi (e.g., mushrooms, molds)
• Earthworms
• Millipedes

d) Function of each part of the mammalian ear:

i) Pinna: Collects sound waves from the environment and directs them into the ear canal.

ii) Cochlea: Converts sound vibrations into electrical signals (nerve impulses) that are sent to the brain for interpretation. It is responsible for hearing.

iii) Eustachian tube: Equalizes air pressure between the middle ear and the outside atmosphere, preventing damage to the eardrum.

iv) Semi-circular canal: Detects rotational movements of the head and helps maintain balance and spatial orientation.

5.

a)

i) Demagnetization of a magnet is the process of removing or reducing the magnetic properties of a material, causing it to lose its magnetism.

ii) Three ways by which a magnet could be demagnetized are:

• Heating: Heating a magnet above its Curie temperature causes its magnetic domains to become disoriented.
• Hammering/Dropping: Repeatedly striking or dropping a magnet causes the magnetic domains to become misaligned.
• Alternating current (AC) demagnetization: Placing the magnet in a strong alternating magnetic field and slowly withdrawing it, or slowly reducing the AC current to zero.

b)

i) A hazardous substance is any substance that can cause harm to humans, animals, or the environment due to its chemical or physical properties (e.g., toxicity, flammability, corrosivity).

ii) Name one:

• (a) Corrosive household substance: Bleach (e.g., sodium hypochlorite solution) or drain cleaner.
• (b) Inflammable laboratory substance: Ethanol or acetone.
• (c) Toxic laboratory substance: Mercury or cyanide compounds.

c) Explanation of breeding systems of farm animals:

i) Hand mating: This is a controlled breeding system where the male and female animals are brought together for mating under direct human supervision. It allows for precise record-keeping, prevents indiscriminate breeding, and ensures that specific animals are bred.

ii) Pasture mating: This is a natural breeding system where male and female animals are allowed to roam freely together in a pasture or enclosure, and mating occurs without direct human intervention. It is less labor-intensive but offers less control over breeding records and specific pairings.