(a)

Observe the graph.

The rate of increase is initially very small, because slope is very less.

And then increases to a maximum at $\"\"$ h, then decreases towards zero.

(b)

When $\"\"$ h, the rate is higher because here slope is high when compare to all other points.

(c)

Observe the graph.

The tangent line to the graph lies below the graph.

Therefore the graph is concave up over the interval $\"\"$ .

The tangent line to the graph lies above the graph.

Therefore the graph is concave down over the interval $\"\"$ .

(d)

Observe the graph.

The graph changes the concavity from up to down at $\"\"$ h.

Therefore the graph has a inflection point at $\"\"$ .

(a) The rate of increase is initially very small, then increases to a maximum at $\"\"$ h, then decreases towards zero.

(b) When $\"\"$ h the rate is higher.

(d) Inflection point is at $\"\"$ .