Q: 97 (NDA-I/2009)

Consider the following statements regarding diamond :
1. It is an allotrope of silicon.
2. It is a bad conductor of heat and electricity.
3. Tt is the hardest substance.
4. It burns to produce carbon dioxide
Which of the statements given above are correct?
question_subject: 
Science
stats: 
0,792,176,80,792,64,32