Read the passage on crude mineral oil and answer the question: From where does mineral oil originate according to the passage?

Introduction / Context:
This reading comprehension question focuses on the origin of mineral oil as explained in the passage. It tests whether you can identify and retain specific factual information about how crude oil is formed over long geological periods. Such questions are typical of science based passages in competitive exams.

Given Data / Assumptions:

• The passage states that "Mineral oil originates from the carcasses of tiny animals and from plants that live in the sea."
• It further explains that these dead organisms form large deposits under the seabed, which are later transformed into crude oil.
• Options mention complex mixtures, lakes, only plants, and the combination of animals and plants.
• We assume students have read the full passage just before attempting the question.

Concept / Approach:
The question is asking for the source or origin of mineral oil, not for its definition or composition. The passage clearly mentions both "carcasses of tiny animals" and "plants that live in the sea" as the initial organic matter. Therefore, the correct option must include both of these, and not restrict the source to only plants or other locations like lakes.

Step-by-Step Solution:
Step 1: Locate the relevant sentence in the passage: "Mineral oil originates from the carcasses of tiny animals and from plants that live in the sea." Step 2: Note that there are two sources: tiny sea animals and sea plants. Step 3: Examine option A: "Complex mixture of substances." This describes the nature of crude oil, but not its origin. Step 4: Examine option B: "Carcasses of tiny animals and plants that live in the sea." This exactly matches the sentence from the passage. Step 5: Examine option C: "From lakes." Lakes are not mentioned in the passage as the origin of mineral oil. Step 6: Examine option D: "Only from plants." This ignores the role of animal carcasses mentioned in the passage.

Verification / Alternative check:
If you re-read the explanation of how crude oil forms, the passage clearly describes dead marine animals and plants accumulating on the seabed, being covered by sand and silt, and then turning into oil under pressure and heat. There is no mention of lakes, land plants only, or any single source. The mixture of animal and plant remains is essential. Option B is the only one that captures both elements without leaving anything out or adding new information.

Why Other Options Are Wrong:

• Complex mixture of substances: This describes what crude oil is, not where it originates from.
• From lakes: The passage specifically mentions the sea and seabed, not lakes, so this is incorrect.
• Only from plants: Omits the equally important contribution of tiny animal carcasses, contradicting the passage.

Common Pitfalls:
Candidates sometimes confuse different parts of the passage, mixing up the definition of crude oil with its origin. Others may remember only "plants" and forget that animals are mentioned too. To avoid such mistakes, it helps to underline or mentally mark key phrases such as "carcasses of tiny animals" and "plants that live in the sea" while reading. Paying attention to words like "and" or "only" in the options is also crucial, as they can completely change the meaning.

Final Answer:
According to the passage, mineral oil originates from the carcasses of tiny animals and plants that live in the sea.