A researcher is modeling the concentration of a chemical reactant, $C$, as it decomposes over discrete time steps. The reaction halts when the concentration falls to or below a safety threshold, $T$.

The two subroutines below, Figure 1 and Figure 2, are designed to count the number of steps required for the concentration to reach this safe level.

Figure 1

SUBROUTINE decompose_steps(C, T)
  steps ← 0
  REPEAT
    C ← C * 0.85
    steps ← steps + 1
  UNTIL C <= T
  RETURN steps
ENDSUBROUTINE

Figure 2

SUBROUTINE decompose_steps(C, T)
  steps ← 0
  WHILE C > T
    C ← C * 0.85
    steps ← steps + 1
  ENDWHILE
  RETURN steps
ENDSUBROUTINE

Describe two differences in the way the loops in Figure 1 and Figure 2 operate.