**Explanation:**

Mercury is an ideal liquid used in a thermometer because it possesses several properties that make it suitable for this purpose. Let's discuss each property in detail:

**a) It expands a lot on heating:**
- One of the main properties of a liquid used in a thermometer is that it should expand when heated and contract when cooled. This property allows the liquid to accurately measure changes in temperature.
- Mercury expands significantly when heated, making it an ideal choice for a thermometer. This expansion is linear and predictable, which means that small changes in temperature can be accurately measured.

**b) It does not stick to glass and is visible:**
- Another important property of a liquid used in a thermometer is that it should not stick to the glass and should be easily visible.
- Mercury does not stick to the glass walls of the thermometer, allowing it to freely rise and fall within the capillary tube.
- Additionally, mercury has a silvery appearance, making it highly visible and easy to read.

**c) It has a high boiling temperature:**
- The boiling temperature of a liquid is an important consideration for a thermometer. It should have a high boiling temperature to ensure that it remains in a liquid state within the thermometer's operating range.
- Mercury has a relatively high boiling temperature of 356.7°C (674.1°F), which allows it to remain in a liquid state at high temperatures encountered in everyday applications.
- This property ensures the longevity and accuracy of the thermometer, as the liquid does not evaporate or change state during normal use.

**d) All of the above:**
- Considering all the properties discussed above, mercury possesses all the necessary characteristics to be an ideal liquid used in a thermometer.
- Its expansion on heating, non-stickiness to glass, high visibility, and high boiling temperature make it a reliable and accurate choice for temperature measurement.

In conclusion, mercury is an ideal liquid used in a thermometer because it expands significantly on heating, does not stick to glass, and is highly visible. Additionally, it has a high boiling temperature, ensuring its effectiveness and reliability as a temperature measurement medium.

Some of the good qualities of mercury which make it ideal for use in thermometers are:

1.It is opaque. 
2. It remains liquid over a wide range of temperature. Its boiling point is high and freezing point is low. 
3. Has low vapour pressure. 
4.Coefficient of expansion is high. Little heating produces more expansion. 
5. Specific heat is low. Small heat produces more increase of temperature and thus more expansion. It makes measurement accurate. 
6. Does not stick (wet) on the walls of glass. 
7. Does not react with glass.