Quartz have the less solubility during weathering. <span>Quartz is the rock forming mineral least susceptible to chemical attack at Earths surface.So rocks rich in quartz tend to have poor solubility during weathering.</span>
In geology, a key bed (syn marker bed) is a relatively thin layer of sedimentary
rock that is readily recognized on the basis of either its distinct
physical characteristics or fossil content and can be mapped over a very
large geographic area.[1]
As a result, a key bed is useful for correlating sequences of
sedimentary rocks over a large area. Typically, key beds were created as
the result of either instantaneous events or (geologically speaking)
very short episodes of the widespread deposition of a specific types of sediment. As the result, key beds often can be used for both mapping and correlating sedimentary rocks and dating them. Volcanic ash beds ( and bentonite beds) and impact spherule beds, and specific megaturbidites
are types of key beds created by instantaneous events. The widespread
accumulation of distinctive sediments over a geologically short period
of time have created key beds in the form of peat beds, coal beds, shell beds, marine bands, black in cyclothems, and oil shales. A well-known example of a key bed is the global layer of iridium-rich impact ejecta that marks the Cretaceous–Paleogene boundary (K–T boundary). Please let me know if it works.
Chloroplast has evolved from photosynthetic bacteria
Answer: The correct answer is C) Specialized.
Cells that have their own unique structures and functions are called as specialized cells. These cells are present in multicellular organisms. For performing specific function, they have unique adaptations in their structures.
For example- Nerve cells. They receive and transmit nerve impulses from one part to another part of the body. They are connected to other nerve cells or muscle cells in the body. The typical structure of nerve cell consists of body, dendrite, and exon.
As it performs the specific function, therefore, it is an example of specialized cell.
