Earth's crust is made of rock, and rock is made of natural substances called minerals. There are three main types of rock: sedimentary, igneous, and metamorphic rock. Each type is produced in different ways. The oldest rocks on Earth were formed about 3.8 billion years ago.
Minerals are naturally occurring substances formed by geological processes. They are usually solid and feature a crystal structure as well as specific physical properties and chemical composition.
Physical properties of minerals include crystal structure, hardness (Mohs scale), lustre (how it reflects light) and color, as well as more complicated properties such as streak, fracture, cleavage and density.
Mohs scale of hardness measures the ability of minerals to scratch each other. Talc is very soft and is listed as 1, diamond is very hard and is measured as 10.
A mineral is sometimes made up of just one chemical element but more often it is a compound (mixture) of two or more.
For example, diamond is made up of just carbon, while fluorite is made up of a compound of calcium and fluorine.
There are over 4000 different types of minerals.
Only around 30 of these are commonly found in the Earth's crust.
Examples of minerals include calcite, gypsum, feldspar, pyrite, gold, quartz and diamond.
The precious gems ruby and sapphire are varieties of the mineral corundum.
Rocks
Rocks and stones are naturally occurring solids made up of minerals.
The Earth's crust is made up of rock.
Rocks have been used by humans for millions of years, from early tools and weapons through to various construction materials.
There are three different types of rocks based on the way they form, igneous, sedimentary and metamorphic.
When magma cools and solidifies it forms igneous rock.
Examples of igneous rocks include granite, basalt, gabbro, obsidian and pumice. More igneous rock facts.
Sediment deposited over time, often as layers at the bottom of lakes and oceans, forms sedimentary rocks.
Examples of sedimentary rocks include sandstone, mudstone, flint, greywacke and chalk. More sedimentary rock facts.
Extreme pressure and heat over time forms metamorphic rocks.
Examples of metamorphic rocks include marble, quartzite, schist, granulite and slate. More metamorphic rock facts. The metamorphic rock marble is formed from the sedimentary rock limestone.
The metamorphic rock granulite is formed from the igneous rock basalt.
Complete question: A phylogenetic tree shows that birds and crocodiles share many features. A hypothesis based on this tree predicts that these features are present in a common ancestor. Which of these predicted traits is supported by fossil evidence?
A) four-chambered heart
B) singing for territory
C) eggs and nests
D) singing to attract mates
Answer: (c) eggs and nests
Explanation:
A hypothesis based on phylogenetic tree shows that birds and crocodiles have ancestral connection. Fossil evidence shows that their common ancestor exhibit oviparity as a means of reproduction (i.e. laying of eggs and embryo develops within the egg), and also housed their eggs in the nest for protection against predators and other important reasons.
Chargaffs rules states that dna from any cell of all organisms should <span>have a 1:1 ratio (base Pair </span>Rule<span>) of pyrimidine and purine bases and, more specifically, that the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine.</span>
Answer: The infrared radiations can detect the coolest and dimmest space objects.
In general, the coolest and darkest regions of space emit radiations of longer wavelengths. The Infrared telescope is used to find the cool, dim stars by slicing the interstellar dust bands and also measure the temperature of the planet of the solar system. The coldest stars do not emit light so they can be seen with the infrared telescopes only. In the visible region, blue stars are hottest and red are the coolest. The wavelength is inversely proportional to the energy emitted so the hottest stars are in the region of low wavelength in visible region.
A normal range in adults is generally considered to be 4.35 to 5.65 million red blood cells per microliter (mcL) of blood for men and 3.92 to 5.13 million red blood cells per mcL of blood for women. In children, the threshold for high red blood cell count varies with age and sex.
