In the passage about energy in India, choose the correct verb to complete the third blank: firewood, cow-dung cakes and vegetable waste etc. _____ non commercial forms of energy.

Introduction / Context:

This question continues the same cloze passage on energy in India. The sentence now shifts attention from commercial energy sources to non commercial ones such as firewood, cow dung cakes, and vegetable waste. You need to select the verb that correctly describes how these items relate to non commercial forms of energy.

Given Data / Assumptions:

Concept / Approach:

The appropriate verb for describing a set of items that make up or form a group is constitute. We often say A, B, and C constitute X when those items together form or represent X. In this sentence, domestic fuels like firewood and cow dung cakes together constitute non commercial forms of energy. Words like combine and mix describe physical or abstract processes rather than classification, and collaborate refers to people working together, not objects forming a category.

Step-by-Step Solution:

Verification / Alternative check:

Compare this sentence with similar ones used in social science texts: Coal and petroleum constitute the main sources of commercial energy. Traditional fuels such as wood and cow dung constitute non commercial energy sources in rural areas. The structure A, B, and C constitute X is standard. This confirms that the passage is expected to use constitute. Reading the complete sentence with this verb results in smooth and precise English: On the other hand, firewood, cow-dung cakes and vegetable waste etc. constitute non commercial forms of energy.

Why Other Options Are Wrong:

Common Pitfalls:

Some students choose combine or mix because they see a list of items and think of them acting together. The key is to understand that the sentence is about classification, not physical joining. Whenever you see a list followed by a description of what they are collectively called, the verb constitute is often the most precise and formal choice. Remembering this collocation will help in many cloze test and writing situations.

Final Answer:

The correct verb for the third blank is constitute.