At atmospheric pressure ices crystallised in the ......... form but at very low temperature it condenses to ......... form.

Answer

To answer the question, we need to identify the forms of ice that crystallize under different conditions.

1. **Understanding Ice Forms**: At atmospheric pressure, ice typically crystallizes in a hexagonal form. This is the most stable structure of ice at normal conditions. The hexagonal form is known as Ice Ih, which is the common form of ice that we see in nature.

2. **Low Temperature Conditions**: When we consider very low temperatures, ice can condense into a cubic form. This cubic form of ice is known as Ice Ic. It is less stable than Ice Ih and exists under specific conditions, particularly at very low temperatures.

3. **Final Answer**: Therefore, the complete statement is: "At atmospheric pressure, ice crystallizes in the hexagonal form, but at very low temperature, it condenses to the cubic form."

### Step-by-Step Solution:
1. **Identify the conditions**: Atmospheric pressure and low temperature.
2. **Determine the form of ice at atmospheric pressure**: Ice crystallizes in the hexagonal form.
3. **Determine the form of ice at very low temperature**: Ice condenses to the cubic form.
4. **Combine the findings into a complete statement**: "At atmospheric pressure, ice crystallizes in the hexagonal form, but at very low temperature, it condenses to the cubic form."