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A team of scientists placed five rocks in five separate, artificial environments. All the rocks came from the same formation and had the same chemical composition. The table describes the environment for each rock.

\begin{tabular}{|c|c|c|c|c|}
\hline Rock A & Rock B & Rock C & Rock D & Rock E \\
\hline
\begin{tabular}{l}
- intermittent rain showers \\
- temperatures alternating \\
between [tex]$-2^{\circ} C$[/tex] and [tex]$20^{\circ} C$[/tex]
\end{tabular} &
\begin{tabular}{l}
frequent acidic showers \\
that contain carbonic acid
\end{tabular} &
\begin{tabular}{l}
covered with algae and lichen
\end{tabular} &
\begin{tabular}{l}
placed in an oxygen-rich environment
\end{tabular} &
\begin{tabular}{l}
- hot and dry environment \\
- low temperature of [tex]$35^{\circ} C$[/tex]
\end{tabular} \\
\hline
\end{tabular}

After the experiment, the scientists observed that one particular rock had large fractures and had split into two pieces. They also observed that, compared to the other rocks, the chemical composition of this particular rock had remained largely unchanged. Which rock most likely fits this description?

A. Rock A
B. Rock B
C. Rock C
D. Rock D
E. Rock E



Answer :

GinnyAnswer
To determine which rock most likely fits the description of having large fractures, split into two pieces, but with largely unchanged chemical composition, let's analyze the conditions each rock was subjected to and their potential effects:

1. Rock A:
- Environment: Intermittent rain showers and temperatures alternating between -2°C and 20°C.
- Effects: The temperature fluctuations between freezing and thawing can cause physical expansion and contraction in the rock, leading to physical fractures. However, since this is mainly a physical process, the chemical composition of the rock would likely remain unchanged.

2. Rock B:
- Environment: Frequent acidic showers containing carbonic acid.
- Effects: Acidic rain can cause chemical weathering and dissolve certain minerals within the rock, altering its chemical composition.

3. Rock C:
- Environment: Covered with algae and lichen.
- Effects: Biological weathering from algae and lichen can lead to the production of organic acids, which would react with the minerals in the rock and change its chemical composition.

4. Rock D:
- Environment: Placed in an oxygen-rich environment.
- Effects: Oxygen-rich environments can cause oxidation processes, which would change the chemical composition of the rock, especially if it contains iron or other oxidizable minerals.

5. Rock E:
- Environment: Hot and dry environment with a low temperature of 35°C.
- Effects: Though a hot and dry environment can lead to some physical weathering due to thermal expansion and contraction, the low temperature of 35°C is unlikely to cause severe physical fractures. Additionally, there would be minimal, if any, chemical changes in such conditions.

Given these analyses, Rock A best fits the description: the temperature fluctuations between -2°C and 20°C create an environment conducive to physical weathering (fractures) without significant chemical alteration. Thus, the rock remains chemically unchanged despite splitting into two pieces due to physical stresses.

Therefore, the rock that most likely fits the description is:

A. Rock A

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