The question asks for the definition of a rock. We need to evaluate each option based on geological definitions of rocks.
Correct Option: D) Any natural solid material forming the Earth's crust, hard like granite or soft like clay
This option provides the most comprehensive and accurate definition of a rock. Rocks are natural solid materials that make up the Earth's crust. They can be hard (like granite, basalt, sandstone) or soft (like clay, shale, or even loose sand and gravel, which are considered unconsolidated rocks). This definition correctly includes the wide variety of materials that constitute the Earth's lithosphere.
The question asks for the specific scientific discipline that focuses on the study of rocks. We need to identify the correct term among the given options by understanding the scope of each field.
Correct Option: A) Petrology is the branch of geology that studies rocks, including their origin, composition, structure, and classification.
The question asks to identify the most common mineral found in rocks. This requires knowledge of the relative abundance of common rock-forming minerals in the Earth's crust.
Correct Option: A) Feldspar is the most common mineral group in the Earth's crust, making up approximately 60% of its weight. It is a fundamental component of many igneous, metamorphic, and sedimentary rocks.
The question asks for the broad classification of rocks. This is a fundamental concept in geology. Rocks are generally categorized based on their formation processes.
Correct Option: B) Three (Igneous, Sedimentary, Metamorphic)
This option correctly identifies the three major types of rocks based on their formation processes, which is the universally accepted geological classification.
The question asks for the definition of a mineral. To answer this, we need to recall the key characteristics that define a substance as a mineral in geology and mineralogy.
Correct Option: A) A naturally occurring inorganic substance with a definite chemical composition and orderly atomic structure. This option accurately captures all the five universally accepted criteria for defining a mineral: naturally occurring, inorganic, solid, definite chemical composition, and orderly atomic structure (crystalline structure). The term "solid" is implied by "substance" in this context, as minerals are solids.
The question asks to identify which option is NOT a physical property used for mineral identification. We need to recall the common physical properties used by geologists to distinguish different minerals.
Correct Option: A) Age