Iwill give you brainilestwhich of the following statements  best  describes chemical weathering?               a.  it's the process by which rocks and minerals undergo changes in their composition.      b.  it always results in dome-shaped formations.      c.  it's the type of weathering in which rocks and minerals break down into smaller pieces.      d.  it happens only in cool environments.

Consider the growth of a 20-nm-diameter silicon nanowire onto a silicon wafer. the temperature of the wafer surface is maintained at 2400 k. assume the thermal conductivity of the silicon nanowire is 20 wm-1k-1 and all its surfaces including the tip are subjected to convection heat transfer with the coefficient h = 1×105 wm-2k-1 and t∞ = 8000 k. when the nanowire grows to l = 300 nm, what is the temperature of the nanowire tip (t (x =