The conventional rule is to take the plural form of the verb when two nouns are joined by the conjunction 'and'. However, there are exceptions. Only then can you break the rule.
When the two nouns refer to one thing only, then you can use the single form. For example: The president and the CEO joins the meeting today. In this example, the president and CEO apply to one person only. Hence, you use the singular form of the verb.
Electricity fueled by coal is one of the biggest causes of global warming.
This sentence shows the main idea of the passage. From the answer choices, it is clear that the passage explains how burning coal creates electricity. It includes details such as "coal is burned to heat water and turn it into steam" which then "turns turbines connected to generators." It goes on to explain how it is dangerous to the environment. The passage states that "burning coal gives off a variety of other harmful chemicals...these gases, along with carbon dioxide, are the main causes of the greenhouse effect." All of these details support the main idea that electricity fueled by coal is one of the biggest causes of global warming.
<span>The speaker's credibility.
By definition, ethos is an appeal to credibility by an author or writer in general</span>