As stars and planets originate from the same cosmic gas and dust, certain astronomers theorize that host stars (e.g., the Sun) and their associated planets (e.g., those in our solar system) share identical compositions. They propose that planets possess either equal or lesser amounts of the materials present in their host stars. This concept finds support in the observation that rocky planets within our solar system share common materials with the Sun.

Which finding, if true, would most directly weaken the astronomers’ claim?

A short passage helps to draw a conclusion from the given passage.

The details and facts help to draw the main idea of the passage.

Can you summarize what you’ve understood in the above steps?

Choice A is correct and is selected as the most suitable option since it introduces evidence that could undermine astronomers' assertions regarding the composition of host stars and their planets. Specifically, it suggests that the elevated iron content in certain rocky planets contradicts the expected pattern of material distribution.

Evidence emerges that the amount of iron in some rocky planets are considerably higher than the amount in their host star.

Choice B is incorrect because a discovery solely concerning the composition of stars, regardless of whether they’ve cooled, would not offer insights into the constituents of planets. Consequently, it wouldn’t affect the claim regarding their shared materials.

Stars are made of hydrogen and helium, and when cooled, they are revealed to iron and silicate.

Choice C is deemed erroneous because a discovery indicating comparable proportions of certain materials in two host stars would not shed light on the composition of planets. Hence, it wouldn’t address the assertion regarding shared materials.

A nearby host is observed to have the same ratio of hydrogen to helium as the sun at it’s start.

Choice D is incorrect as the astronomers' assertion stems from the established fact that stars and planets originate from the same cosmic materials, irrespective of the effectiveness of compositional analysis methods.

The method for determining the composition of rocky planets are discovered to be less effective when used to analyze other kinds of planets.

Correct sentence

The main idea of the passage - Evidence emerges that the amount of iron in some rocky planets are considerably higher than the amount in their host star.

Option

A

Can you summarize what you’ve understood in the above steps?