How can you say that photosynthesis is the basic energy source for living world

we can analyse this topic by taking a look at the reaction of photosynthesis

CO2+H2O+LIGHT>C6H12O6+O2

we can see that one form of energy(light energy) has been stored in the chemical bonds(glucose)

if we look at the chemical reaction for aerobic respiration(the way we obtain energy)

C6H12O6+O2CO2+H20+energy

we can see that the energy stored in the bonds has been released

also respiration reactants are photosynthesis produts

Wishing you and your family health, happiness, peace and prosperity this Christmas and in the coming New Year.

answer:

convection currents in the magma drive plate tectonics. heat generated from the radioactive decay of elements deep in the interior of the earth creates magma (molten rock) in the aesthenosphere. the aesthenosphere (70 ~ 250 km) is part of the mantle, the middle sphere of the earth that extends to 2900 km.