Most earthquakes occur along the edge of the oceanic and continental plates. The earth's crust (the outer layer of the planet) is made up of several pieces, called plates. The plates under the oceans are called oceanic plates and the rest are continental plates. The plates are moved around by the motion of a deeper part of the earth (the mantle) that lies underneath the crust. These plates are always bumping into each other, pulling away from each other, or past each other. The plates usually move at about the same speed that your fingernails grow. Earthquakes usually occur where two plates are running into each other or sliding past each other.
The answer is C :
It controls the entry and exit of substances.
Explanation:
A covalent bond is formed when an element shares its valence electron with another element. This bond is formed between two non metals.
An ionic bond is formed when an element completely transfers its valence electron to another element. The element which donates the electron is known as electropositive element and the element which accepts the electrons is known as electronegative element. This bond is formed between a metal and an non-metal.
Chlorine and potassium atoms form ionic bonds: Ionic bond is formed when there is complete transfer of electron from a highly electropositive metal to a highly electronegative non metal. Electronegativity difference = electronegativity of chlorine - electronegativity of potassium = 3-0.8 = 2.2
Carbon atoms form non-polar covalent bonds with nitrogen atoms : Non-polar covalent bond is defined as the bond which is formed when there is no difference of electronegativities between the atoms. Electronegativity difference = electronegativity of nitrogen - electronegativity of carbon= 3.0-2.5 = 0.5
Oxygen forms polar covalent bonds with phosphorus: A polar covalent bond is defined as the bond which is formed when there is a difference of electronegativities between the atoms. Electronegativity difference = electronegativity of oxygen - electronegativity of phosphorous = 3.5- 2.19 = 1.31
