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Select the correct answer.

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



Answer :

GinnyAnswer
To determine which rock most likely fits the description of having developed large fractures and having its chemical composition remain largely unchanged, we need to analyze the conditions for each rock and their potential impacts.

1. Rock A:
- Conditions: Intermittent rain showers, temperatures alternating between -2°C and 20°C.
- Analysis: The temperature fluctuations between freezing (-2°C) and thawing (20°C) could cause stress fractures through freeze-thaw cycling, but there might be some chemical change due to weathering.

2. Rock B:
- Conditions: Frequent acidic showers that contain carbonic acid.
- Analysis: Acidic conditions are likely to cause significant chemical reactions altering the chemical composition of the rock.

3. Rock C:
- Conditions: Covered with algae and lichen.
- Analysis: Biological growth such as algae and lichen can lead to chemical changes in the rock over time through biological weathering.

4. Rock D:
- Conditions: Placed in an oxygen-rich environment.
- Analysis: An oxygen-rich environment can cause oxidation, which alters the chemical composition of the rock.

5. Rock E:
- Conditions: Hot and dry environment with a low temperature of 35°C.
- Analysis: A hot and dry environment with relatively stable conditions (low temperature variation) is least likely to change the chemical composition of the rock. However, such conditions might cause physical stress leading to the formation of fractures.

Given these analyses:

- Rock A may fracture due to freeze-thaw cycling but is susceptible to some chemical change due to weathering.
- Rock B is likely to undergo significant chemical changes due to acids.
- Rock C is prone to chemical changes from biological growth.
- Rock D will undergo oxidation, changing its chemical composition.
- Rock E remains chemically stable due to the low likelihood of chemical reactions in hot and dry conditions, but might develop fractures due to physical stress.

Based on this reasoning, the rock that most likely developed large fractures and remained largely chemically unchanged is:

Rock E

Thus, the correct answer is:
E. Rock E