What are the benefits of microbes in food processing, the definition of enzymes, and methods/factors of fertilizer application?

Frequency ($f$) = 500 Hz
Wavelength ($\lambda$) = 80 m

The speed of a wave ($v$) is given by the formula: $v = f \times \lambda$

4(b)α
Malnutrition is a condition that results from a diet in which nutrients are either not enough or are too much, such that the diet causes health problems. It can involve undernutrition (insufficient intake of energy and nutrients) or overnutrition (excessive intake).

4(b)β(i)
One cause of Night blindness is Vitamin A deficiency.

4(b)β(ii)
One cause of High Blood pressure is excessive sodium intake (e.g., from a high-salt diet).

4(b)β(iii)
One cause of Kwashiorkor is protein deficiency.

4(c)α(i)
An assay is an analytical procedure used to qualitatively assess or quantitatively measure the presence, amount, or functional activity of a target entity (e.g., a drug, hormone, or enzyme) in a sample.

4(c)α(ii)
A standard solution is a solution of precisely known concentration, prepared by dissolving an accurately weighed amount of a primary standard substance in a known volume of solvent. It is used as a reference in titrations and other analytical procedures.

4(c)α(iii)
A saturated solution is a solution that contains the maximum amount of solute that can be dissolved in a given amount of solvent at a specific temperature and pressure. Any additional solute added to a saturated solution will not dissolve and will remain as a solid.

4(c)β

Given atomic masses: Na=23, Cl=35.5.
Molar mass of $\text{NaCl} = 23 + 35.5 = 58.5 \text{ g/mol}$

Mass of $\text{NaCl} = 25.5 \text{ g}$

Volume of solution = 2.0 $\text{dm}^3$

4(d)(i)
Two examples of worms that infest farm animals are:

• Roundworms (e.g., Ascaris suum in pigs, Haemonchus contortus in sheep/goats)
• Tapeworms (e.g., Taenia saginata larvae in cattle, Moniezia species in sheep/goats)

4(d)(ii)
Three precautions that could be adopted to reduce worm infestation in farm animals are:

• Regular deworming: Administering anthelmintic drugs to animals at appropriate intervals to kill existing worms.
• Rotational grazing: Moving animals to different pastures periodically to break the life cycle of parasites and reduce the buildup of worm larvae on the land.
• Proper sanitation and hygiene: Regularly cleaning animal housing, disposing of manure properly, and ensuring access to clean feed and water to minimize exposure to worm eggs and larvae.

5(a)
The stages involved in large-scale treatment of water for public consumption are:

1. Screening: Raw water passes through screens to remove large debris like leaves, sticks, and trash.
2. Coagulation and Flocculation: Chemicals (coagulants like alum or ferric chloride) are added to the water to neutralize the charge of suspended particles, causing them to clump together into larger, heavier particles called flocs.
3. Sedimentation: The water flows into large tanks where the heavy flocs settle to the bottom due due to gravity, forming sludge.
4. Filtration: The water passes through filters made of layers of sand, gravel, and sometimes activated carbon, which remove remaining suspended particles, pathogens, and some dissolved impurities.
5. Disinfection: A disinfectant, typically chlorine, is added to kill any remaining bacteria, viruses, and other microorganisms.
6. Fluoridation (Optional): In some areas, fluoride is added to help prevent tooth decay.
7. Storage and Distribution: The treated water is stored in reservoirs or tanks and then distributed to consumers through a network of pipes.