For bryophytes (mosses, liverworts etc.) and seedless vascular plants (ferns), the specific organ that produces the spores on the sporophyte is called the For bryophytes (mosses, liverworts etc.) and seedless vascular plants (ferns), the specific organ that produces the spores on the sporophyte is called the A. Antheridium B. Sporangium C. Aonium D. Sporophyll E. Peristome

B) is the correct option

Explanation:

A sporangium is a structure in certain plants and other organisms that is charged with making and storing spores Spores are haploid structures created in organisms that help to germinate and form new organismsTypically, the plants which develop two types of gametophyte do so within separate microsporangia and megasporangia, these produce microspores and megaspores, which are functionally equivalent to the male (micro) and female (mega) gametesThe term used to describe this trait is heterosporous, and it applies to some bryophytes (non-vascular plants, including liverworts, hornworts and mosses), some lycophytes, a few pteridophytes (ferns)On the other hand, most bryophytes are homosporous which means they produce only one type of spore within the sporangia, which subsequently develops into a monoecious gametophyte possessing both male and female organs                    

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.