Dna plays a major role in heredity, composing the genes that are passed down from parent to offspring. it also plays a major role in the everyday workings of your cells. it does this by creating molecules, such as enzymes, that regulate cell functions.
these enzymes belong to a larger class of molecules known as
a)
rna.
b)
proteins.
c)
ion pumps.
d)
amino acids.

In biochemical reactions, it is mostly triggered by enzymes. Enzymes are important components in the process that involves metabolism and digestive functions, further, most of these enzymes are proteins.Proteins are biological macromolecule and mostly composed of enzymes. Proteins play a role in the physical make-up of a cell or acts as a cytoskeleton –maintains cell shape and figure. These proteins plays different roles and works with nucleic acids and other macromolecules in the cells including cell cycle, cell adhesion, immune response and cell indicators.  

Mantle convection  is the slow  creepingmotion of earth's solid silicate  mantle  caused by  convection  currents carrying  heat from the interior  to the planet's surface.[1][2]  the earth's surface  lithosphere, which rides atop the  asthenosphere  (the two components of the  upper mantle), is divided into a number of  plates  that are continuously being created and consumed at their opposite  plate boundaries. accretion occurs as mantle is added to the growing edges of a plate, associated with  seafloor spreading. this hot added material cools down by  conduction  and  convection  of heat. at the consumption edges of the plate, the material has thermally contracted to become dense, and it sinks under its own weight in the process of  subduction  usually at an  ocean trench.[3]this subducted material sinks through the earth's interior. some subducted material appears to reach the lower mantle,[4]  while in other regions, this material is impeded from sinking further, possibly due to a phase transition from  spinel  to  silicate perovskiteand  magnesiowustite, an  endothermic reaction.[5]the subducted oceanic crust triggers  volcanism, although the basic mechanisms are varied. volcanism may occur due to processes that add buoyancy to partially melted mantle causing an upward flow due to a decrease in density of the partial melt.secondary forms of convection that may result in surface volcanism are postulated to occur as a consequence of intraplate extension[6]  and  mantle plumes.[7]it is because the mantle can convect that the  tectonic plates  are able to move around the earth's surface.[8]mantle convection seems to have been much more active during the  hadean  period, resulting in gravitational sorting of heavier molten  iron, and  nickel  elements and  sulphides  in the core, and lighter  silicate minerals  in the  mantle.