Red roses are dominant to white roses and tall are dominant to short. cross a flower that is homozygous red and tall with a flower that is white and heterozygous tall

All Offsprings will have a red flower and tall phenotype with a genotypic ratio of 1 RrTT : 1 RrTt

Explanation:

This is a cross involving two genes; one coding for rose color and the other for height in rose plant. The red allele (R) is dominant over the white allele (r) in the first gene while tallness (T) is dominant over shortness (t) in the second gene.

Based on this, a homozygous red and tall flower will possess a genotype: RRTT while a flower that is white and heterozygous tall will have genotype: rrTt. Hence, each parent's allele will separate into gametes independently of one another according to Mendel's law of independent assortment. The possible gametes combination are:

RRTT- RT, RT, RT, RT

rrTt- rT, rt, rT, rt.

Hence, using a punnet square (see attached image), all offsprings will possess the phenotypic dominant trait i.e. red and tall. The genotypes produced are: RrTT and RrTt in a ratio 1:1

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.