a. is always a destructive process
b. builds river deltas and sand dunes
c. is the breakdown of rock and soil on earth's surface
d. happens more slowly in warm climate

the way that the mass of carbon can be conserved through cellular respiration is through a process/law called the law of conservation of mass which even tho it undergoes a process, mass is not be destroyed or changed

not sure if this is what you'r looking for nnew= nold