Describe the behavior of the function in the interval [-\ extinf, -1], including its concavity and monotonicity.

Observe the shape of the curve for $x$ values from negative infinity up to $x = -1$.

In the interval $(-\infty, -1]$, the graph of the function is curved downwards, resembling an inverted U-shape. This indicates that the function is concave down (مقعرة نحو الأسفل). The inflection point appears to be at $x = -1$.

In the interval $(-\infty, -1]$, the function is decreasing from $-\infty$ to approximately $x = -2$ (where it reaches a local minimum), and then it is increasing from approximately $x = -2$ to $x = -1$. Therefore, the function is neither strictly increasing nor strictly decreasing over the entire interval $[-\infty, -1]$.

1. مقعرة نحو الأعلى (Concave up): Incorrect, the graph is concave down.
2. مقعرة نحو الأسفل (Concave down): Correct, the graph is concave down in this interval.
3. تزايدية (Increasing): Incorrect, the function is decreasing then increasing.
4. تناقصية (Decreasing): Incorrect, the function is decreasing then increasing.

The correct description for the function in the interval $[-\infty, -1]$ is that it is concave down.

The final answer is $\text{2}$