WAEC 2014 Biology · Question 25

Which of the following substances constitute domestic waste? I Fertilizer II. Insecticides III. Sewage IV. Crude oil V. Sulphur dioxide

Options

A.l only
B.lll only
C.lV only
D.ll and V only

Answer: B. lll only

Explanation written with AI and checked against the answer key

Analyze the question: You are asked to pick the substance(s) that count as domestic waste, meaning waste produced from homes and households.

Explain the concept: Waste is classified by its source:

Domestic waste: comes from homes, such as refuse, food scraps, used water, and sewage (human waste).
Agricultural waste: fertilizers and insecticides/pesticides from farms.
Industrial waste: crude oil spills and gases such as sulphur dioxide from factories, refineries, and burning of fossil fuels.

Step-by-step solution:

I. Fertilizer: used on farms, so it is agricultural waste or pollution. Not domestic.
II. Insecticides: used mainly in agriculture and pest control. Not domestic waste in the standard classification.
III. Sewage: human waste from toilets and households. Domestic.
IV. Crude oil: from oil exploration and refining, so it is industrial. Not domestic.
V. Sulphur dioxide: released by industries and burning fossil fuels. Not domestic.

Only III (sewage) is domestic waste.

Answer: Option B (III only).

Exam tip: Match each pollutant to its source. Think of "farm" for fertilizers and insecticides, "factory or oil company" for crude oil and sulphur dioxide, and "home" for sewage and refuse. Associating the source with the waste type will help you answer most waste-classification questions quickly.

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