Question

read the passage. there are several questions about this passage.

stinkiest place—the rotten egg of io

1
what makes a place stinky? it is quite subjective, really. many scientists believe that smells warn us of potentially harmful chemicals—bad smells indicate things that are bad for us (although this theory does not explain why humans eat liver and onions). however, many things stinky to humans are beneficial to other living things. rats inhabit putrid trash bins, some bacteria eat methane, and flies like poop. so, we have taken a distinctly human perspective to determine the stinkiest place in the solar system. it’s really no contest—jupiter’s moon io produces the biggest stink of all.

2
this is not to say that the solar system lacks stinky places. earth has its fair share—boggy marshes, geothermal areas, landfills, and pig sties, to name a few. new zealand’s 55 million sheep and cattle produce about 90% of the country’s methane emissions (kiwi farmers have fervently opposed a “flatulence” tax). indonesia is home to the exotic and popular durian, a fruit with such an offensive odor that it is banned in singapore hotels and subways. on venus, corrosive clouds of sulfuric acid completely envelop the planet, producing an acrid funk of global proportions. hydrocarbons on saturn’s moon titan fall as toxic precipitation, pool in lakes and streams on the surface, and seep into the underlying goopy soil. titan smells like one big oil refinery.

3
but jupiter’s moon io smells like a jumbo rotten egg. hydrogen sulfide produces the characteristic rotten egg stench, and the stinky compound has been observed both on io’s surface and in the upper atmosphere. in fact, the sheer abundance of sulfur compounds creates the moon’s distinctive red and yellow coloration.

4
during explosive volcanic eruptions—spectacular events that are quite common on io—sulfur gas launches high into the atmosphere. although the mechanism is not completely understood, photochemistry decomposes some of this sulfur gas and forms sulfur dioxide, hydrogen sulfide, and other sulfuric compounds. sulfur molecules freeze on the surface to form red patches near volcano vents. eventually, the red frost turns yellow as sulfur molecules react to form stable sulfur rings.

what main contrast does the author develop in paragraphs 2 and 3?

1. the contrast between pleasant and unpleasant smells in the solar system
2. the contrast between smells found on earth and smells found on nearby planets
3. the contrast between the smell of io and other smelly places in the solar system
4. the contrast between common and uncommon smells on earth and other planets

Explanation:

To solve this, we analyze the content of paragraphs 2 and 3. Paragraph 2 describes smelly places on Earth (like bogs, landfills, pig sties, New Zealand's livestock - related methane, Indonesia's durian) and other celestial bodies (Venus with sulfuric acid clouds, Titan with hydrocarbon precipitation). Paragraph 3 focuses on the smell of Jupiter's moon Io, which is like a rotten egg. The main contrast here is between the smell of Io and other smelly places in the Solar System. Option 1 is incorrect because the passage isn't mainly about pleasant vs. unpleasant smells in the Solar System. Option 2 is wrong as it's not just about Earth vs. nearby planets (Titan and Venus are not "nearby" in the same sense and the focus is on Io vs. others). Option 4 is incorrect as the passage isn't about common vs. uncommon smells.

Answer:

1. the contrast between the smell of Io and other smelly places in the Solar System