I need help please Several hundrer years ago, in a dusty alley in a small North African seaport, a flea jumped onto the back of a dying rat, and bit it. On another continent, millions of people would die because of that flea bite

Disease bacteria from the rat grew inside the flea. The flea hopped onto a passing sailor and bit him, injecting the man with deadly germs.

If the sailor noticed the flea bite, he thought little of it. Vermin were part of his life. Yet only five days out to sea, after a bout of fever, chills, and with ugly discolored lumps under both arms, the sailor's dead body was thrown into the sea. Sickness spread to the crew - and to the ship's rats. The rats passed the disease to more fleas. On arrival in Italy, the ship delivered a carfo of death.

The ship delivered bubonic plague to Europe. The plague spread quickly and killed many. Medieval workers walked the streets chanting, "Bring out your dead!" In an attempt to keep up with all the burials.

If you were a public health worker, what steps would you take to protect people from an epidemic? Be specific.

The answer is option a

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.