1. **Problem statement:**
Given four functions A, B, C, and D with their graphs described, answer the following:
a) Which function is increasing and has the range $y \in \mathbb{R}$ and $y \geq 0$?
b) Find the value of function D at $x=0$.
2. **Step a) Identify the function:**
- Function A is an increasing exponential curve passing through $(0,1)$ and approximately $(1,2)$.
- Function B is a steep increasing line passing through $(0,-2)$, $(1,0)$, and $(2,2)$.
- Function C is an increasing square root curve starting at $(0,0)$, passing through $(1,1)$ and approximately $(2,1.4)$.
- Function D is a downward opening parabola with vertex at $(1,0)$, passing through $(0,-1)$ and $(2,-1)$.
The function must be increasing and have range $y \geq 0$.
- Function A (exponential) is increasing and its range is $y > 0$ (which is $y \geq 0$ if we consider the limit).
- Function C (square root) is increasing and its range is $y \geq 0$.
Since the problem states $y \in \mathbb{R}$ and $y \geq 0$, meaning all real numbers greater or equal to zero, function C fits perfectly.
**Answer:** Function C.
3. **Step b) Find $D(0)$:**
Function D is a downward opening parabola with vertex at $(1,0)$ and passes through $(0,-1)$.
Therefore, the value of function D at $x=0$ is $-1$.
**Answer:** $D(0) = -1$.
Function Properties 405963
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