What does the determination of sex (in humans) have to do with meiosis? How are they related?

Biologically sex is an aggregate of those qualities that differentiate the organisms producing eggs from those organisms producing sperms. The organisms producing eggs are called female and while those producing sperms are called males. "Establishment of male and female or its organ of an organism is called sex determination."

Explanation:

The chief mode of sex determination in most of the organisms is by chromosomes. On the basis of their functions, chromosomes are of following two types:

1.  Autosomes (somatic cell division)

2. Allosomes/sex chromosomes :which are concerned with sex determination and carry genes for determining the sex of an organism.

Meiosis is a specialized and complicated type of cell division which occurs in diploid reproductive cells of gonads and results in formation of haploid(n)sex cells of gametes. The gametes formed as a result of meiosis have got half (n) number of chromosomes as found in the parent cell. Hence it is also known as Reduction Division as a result of this division four daughter cells are formed from a parent cell.

In humans females are homogametic (XX) hence, producing only one type of eggs whereas males are heterogametic(XY) and producing two types of sperms.

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.