1. Primary Succession is: * A. an area that was previously occupied by living things is distributed, then re-colonized
following the disturbance.
B. newly exposed rock is colonized by living organisms for the first time.
C. the ecosystem returns to its original state and it reaches natural equilibrium.
D. all the statements are correct​

Convection occurs when thermal energy is transferred by the movement of

The three classes of rocks are sedimentary, metamorphic, and igneous. how are rocks classified into one of these three groups?

I) a gas contained within a piston-cylinder assembly undergoes two processes, a and b, between the same end states, 1 and 2, where p1 = 10 bar, v1 = 0.1 m3 , u1 = 400 kj and p2 = 1 bar, v2 = 1.0 m3 , u2 = 200 kj: ' process a: process from 1 to 2 during which the pressure-volume relation is pv = constant. ' process b: constant-volume process from state 1 to a pressure of 2 bar, followed by a linear pressure-volume process to state 2. kinetic and potential energy effects can be ignored. for each of the processes a and b, a) sketch the process on a p-v diagram. b) evaluate the work, in kj. c) evaluate the heat transfer, in kj.(ans : qb,12 = -65.0 kj)