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The pericycle is a cylinder of parenchyma or sclerenchyma cells that lies just inside the endodermis and is the outer most part of the stele of plants. [ citation needed ] Although it is composed of non-vascular parenchyma cells, it's still considered part of the vascular cylinder because it arises from the procambium as do the vascular tissues ...
The study of rocks involves multiple subdisciplines of geology, including petrology and mineralogy. It may be limited to rocks found on Earth, or it may include planetary geology that studies the rocks of other celestial objects. Rocks are usually grouped into three main groups: igneous rocks, sedimentary rocks and metamorphic rocks.
Marble is a rock composed of calcium and magnesium carbonate, mostly white and pink. [1] Common marble varieties are granular limestone or dolomite . The hardness of marble is very high, because the internal structure of the rock is very uniform after long-term natural aging, and the internal stress disappears, so the marble will not be ...
The bark of Pinus thunbergii is made up of countless shiny layers. Bark is the outermost layer of stems and roots of woody plants. Plants with bark include trees, woody vines, and shrubs. Bark refers to all the tissues outside the vascular cambium and is a nontechnical term. [1] It overlays the wood and consists of the inner bark and the outer ...
List of rocks on Mars – Alphabetical list of named rocks and meteorites found on Mars; Rock cycle – Transitional concept of geologic time; List of rock formations: for a list of unusual or culturally significant rock outcrops; Leaverite – Rock in the field that looks interesting but is actually not
A stunning 4,000-year-old rock may indicate a previously unknown culture, offering new insights into ancient civilizations. ... Rock art found in southeastern Venezuela may have come from a ...
Metamorphic rocks once existed as igneous or sedimentary rocks, but have been subjected to varying degrees of pressure and heat within the Earth's crust. The processes involved will change the composition and fabric of the rock and their original nature is often hard to distinguish. Metamorphic rocks are typically found in areas of mountain ...
A Petoskey stone is a rock and a fossil, often pebble-shaped, that is composed of a fossilized rugose coral, Hexagonaria percarinata. [1] Such stones were formed as a result of glaciation, in which sheets of ice plucked stones from the bedrock, grinding off their rough edges and depositing them in the northwestern (and some in the northeastern) portion of Michigan's lower peninsula.