The correct answers are:
- at Earth's poles;
- at high latitudes;
- at high latitudes;
The glaciers need specific condition in order for them to exist. The climate has to be cold throughout the year, and the temperature to be bellow 0 degrees in general. If this condition is on place, than the water and humidity in the air will start to freeze. As they freeze they will become bigger and bigger as the ice is increasing its volume, and plus the snow will contribute to its growing as well. This conditions can only be found on the high latitudes, thus in close proximity to the poles, and on the poles themselves as well, ans also on the very high mountains in the mid latitude, like the Alps and the Himalayas.