Which type of rock can be considered as a biological sedimentary rock? 

The correct answer is limestone.

Key PointsSedimentary Rocks

• Sedimentary rocks are formed by the accumulation of sediments.
• Common sedimentary rocks include sandstone, limestone, and shale.
• These rocks frequently start as sediments carried in rivers and deposited in lakes and oceans.
• When secreted, the sediments lose water and become cemented to form rock.

Additional Information

•  Metamorphic Rock is one of the major groups of rock that make up the crust of the Earth; it consists of pre-existing rock mass in which new minerals or textures are formed at higher temperatures and greater pressures than those present on the Earth's surface.
  • Marble is a metamorphic rock that forms when; limestone is subjected to the heat and pressure of metamorphism.
  • A marble that contains impurities such as clay minerals, iron oxides, or bituminous material can be bluish, gray, pink, yellow, or black in color.
  • As metamorphism progresses, the crystals grow larger and become easily recognizable as interlocking crystals of calcite.
  • Some other examples of metamorphic rocks are gneiss, slate, marble, schist, and quartzite.

• Igneous Rock. Igneous rock is a term used for a rock formed when molten rock cools and hardens. Extrusive, or volcanic, igneous rock cools on the surface as lava. Some examples of igneous rocks are granite, gabbro, and basalt.