Provide answers to the following questions regarding plant nutrients, body functions, waste management, mixtures, and work output.

Here is the solution to question 4:

a)

(i) Two micro-nutrients of plants:

• Iron
• Zinc

(ii) Two macro-nutrients of plants:

• Nitrogen
• Potassium

b)

(i) Transport of nutrients: Blood plasma

(ii) Protection of the body against infection: White blood cells

(iii) Temperature regulation: Blood plasma

c)
Three effects of poor waste management on human health:

• Contamination of water sources, leading to waterborne diseases like cholera and typhoid.
• Creation of breeding grounds for disease vectors such as mosquitoes and rats, which spread diseases like malaria and dengue.
• Air pollution from burning waste, causing respiratory problems and other health issues.

d)

(i) Differentiation between a colloid and a suspension:

• A colloid is a heterogeneous mixture where particles are larger than those in a solution but small enough not to settle out. They scatter light (Tyndall effect).
• A suspension is a heterogeneous mixture where particles are large enough to be seen with the naked eye and will settle out over time. They also scatter light.

(ii) Classification of mixtures:
(α) Groundnut paste and water: Suspension
(β) Milk and water: Colloid
(γ) Sugar and water: Solution

e)

(i) Work output:
Work output is the useful work done by a machine. It is the energy transferred by the machine to perform a specific task.

(ii) How work output affects the efficiency of a machine if work input is fixed:
The efficiency of a machine is calculated as the ratio of work output to work input, multiplied by 100%. If the work input is fixed, an increase in the work output will lead to an increase in the machine's efficiency. Conversely, a decrease in work output will result in a decrease in efficiency.