Correct answer: B

Main reasoning: The text defines what a planet is, lists the nine planets, explains their orbits, and mentions the origin of the word “planet.” The whole passage centers on planets, so the most suitable title is “The Planets.”

Option analysis:

A. Stars are mentioned only as objects that planets revolve around; they are not the main focus.

B. Correct, because every paragraph directly discusses planets (definition, names, orbits, and word origin).

C. Orbits appear as an explanation, but the text is broader than only orbits.

D. “Wanderers” is the meaning of the Greek word, but it is only one detail, not the main topic.

E. The Greeks are mentioned for historical naming, but the text is not mainly about Greek people.

Logic note: A title must cover the widest focus; “The Planets” is \( \gt \) “The Orbits” in scope.

Correct answer: E

Main reasoning: The passage states clearly: “All of the planets of the solar system revolve in elliptical orbits.” Therefore, the best completion is “in elliptical orbits.”

Option analysis:

A. The text says planets travel in orbit around stars, but the question asks how they travel; the specific form given is elliptical orbits.

B. “Circles” is only a comparison (“like large, flat circles”), not the exact term used.

C. “One movement” is not stated and is unclear.

D. This describes “wander” in a general sense, not the scientific description of their travel path.

E. Correct, directly taken from the text.

Logic note: “Elliptical orbits” is more precise than “around the stars,” so precision is \( \gt \) generality.

Correct answer: A

Main reasoning: The first paragraph explains that extremely small plants and animals float near the surface and become food for huge numbers of small animals. Those tiny living things are identified collectively as plankton.

Option analysis:

A. Correct: this matches “plants and animals ... extremely small” floating near the surface.

B. Opposite of the text, which emphasizes extremely small organisms.

C. Ocean mammals are mentioned later (whales), but they are not the tiny surface organisms.

D. Too narrow and unclear; the text refers to very small plants and animals in large numbers, not one “smallest animal.”

E. The text includes plants and animals, not only plants.

Logic note: Surface plankton are “extremely small,” so their size is \( \lt \) big animals.

Correct answer: B

Main reasoning: Paragraph \( 3 \) begins with the key idea: “The blue whale is the largest animal ever to live,” followed by size details (over \( 100 \) feet) and comparison to other whales. Although movement/migration is mentioned, the paragraph is anchored by whale size and “largest” emphasis.

Option analysis:

A. Too general; the paragraph is not mainly about habits as a whole, but about size and examples.

B. Correct: “largest animal,” “over \( 100 \) feet,” and “smaller kind” directly signal size comparison.

C. Movement is included for grey whales, but it is not the central framing of the paragraph.

D. Three whales are mentioned, but listing kinds serves the explanation; it is not the main focus.

E. Migration is only one part (grey whale), while the paragraph begins with size as the headline point.

Logic note: The size theme is supported by “largest” and “smaller,” meaning \( \text{blue whale size} \gt \text{humpback whale size} \).

Correct answer: E

Main reasoning: The passage opens with a broad statement about the sea containing millions of plants and animals, then supports it with examples: plankton, whales, sharks, deep-sea fish, jellyfish, and turtles. That opening idea is the best overall summary.

Option analysis:

A. Partly related, but the passage is not mainly about “most plants” as food.

B. Incorrect focus; “blue” is a name, not a discussion point, and colour is not emphasized.

C. A detail about grey whales, not the main information.

D. A supporting detail (whale shark, whales), not the main message.

E. Correct: this is the broad theme that frames all later examples.

Logic note: A main idea must include all examples; “millions of plants and animals” is \( \gt \) any single-detail option.

Correct answer: A

Main reasoning: The jellyfish paragraph states: “Although they contain a powerful sting, they are often eaten by turtles.” This directly supports A.

Option analysis:

A. Correct: explicitly stated that turtles often eat jellyfish.

B. False: the text says turtles spend most of their eggs on sandy beaches, not seabed.

C. False: the powerful sting belongs to jellyfish, not sharks.

D. False: grey whales spend summer feeding in the Arctic and swim south in winter.

E. False: the text says the blue whale is the largest animal ever to live.

Logic note: Summer in the Arctic and winter in Mexico means \( \text{Arctic in summer} \gt \text{Arctic in winter} \) for grey whales’ location.

Correct answer: C

Main reasoning: “Despite” means “in spite of.” The sentence “Despite their great size, certain whales live entirely on plankton” keeps the same meaning when replaced with “In spite of their great size...”

Option analysis:

A. “Therefore” shows result, not contrast.

B. “Referring to” does not express contrast.

C. Correct: direct synonym for “despite.”

D. “Except” indicates exclusion, not contrast.

E. “Instead of” indicates substitution, not contrast.

Logic note: Contrast markers show unexpected relation; contrast is \( \gt \) simple cause-effect here.