In geology and earth science, what is the specialised name for the scientific study of rocks and their origin, composition, and structure?

Introduction / Context:
This question focuses on earth science vocabulary and asks for the precise term used for the study of rocks. While geology covers the broader study of the Earth as a whole, there is a narrower branch that deals specifically with rocks, their formation, and their classification. Recognising the right term is important in science sections of general knowledge tests.

Given Data / Assumptions:

• The object of study is rocks.
• The question seeks the specialised name for this study.
• Options include geology, cytology, petrology, and a misspelled variation petology.
• Only one option accurately names the field devoted to rock studies.

Concept / Approach:
Petrology is the branch of geology that deals specifically with rocks, including igneous, sedimentary, and metamorphic types. It examines their mineral composition, texture, origin, and transformation. Geology is the broader discipline that studies Earth processes, landforms, and materials, but it is less specific than petrology. Cytology is the study of cells in biology, and petology as written with one r is simply an incorrect spelling often used as a distractor.

Step-by-Step Solution:
Step 1: Recognise that the key word in the question is rocks. Step 2: Recall that petrology is defined in textbooks as the science of rocks, a focused subfield under geology. Step 3: Compare with geology, which is more general and covers many topics beyond rocks, such as earthquakes and plate tectonics. Step 4: Choose petrology as the most accurate term and reject cytology and the incorrect spelling petology.

Verification / Alternative check:
Verification can be obtained from earth science glossaries or science textbooks, which list petrology as the branch of geology dealing with the origin, composition, and structure of rocks. Course descriptions at universities also mention petrology as a special subject dealing with igneous and metamorphic rocks, confirming the usage.

Why Other Options Are Wrong:
Geology, while related, is the umbrella term and not the specific name for rock study that the question asks for. Cytology belongs to biology and focuses on cells, not rocks. Petology as written in the option is a common distractor created by intentionally misspelling petrology and has no standing as a recognised scientific discipline.

Common Pitfalls:
Some learners hurriedly select geology because they know it is related to Earth and rocks, without noticing that the question is asking for a specialised term. Others fall into the spelling trap and pick petology because it looks similar while not being correct. Careful reading of both the question and the options and awareness of common distractor patterns can help avoid such errors.

Final Answer:
Petrology