The multiple convection cells in each hemisphere are a phenomenon resulting from the rotation of the earth, which is the rotation that the planet performs around itself, that is, around its own axis.
Earth's convection currents are the endogenous forms of movement of the magma contained below the earth's crust, in the layer we know as the mantle. These currents are also called convection cells because they have a cyclic movement up and down the planet's internal fluids. Convection currents are the main cause of tectonic plate movement and also guide the direction in which this displacement occurs.
When there are <em>multiple convection cells in each hemisphere</em>, something called <u>"The Coriolis effect"</u> happens. The defination is basically that the Earth rotates perpendicular to it's axis which is answer A.
Have you got the list of characteristics on you? If not, both contain cells with chloroplasts, which is used to carry out the photosynthesis. Hope this helps.
