Use the substances named in the table to answer the following questions.
name of substance
argon
carbon dioxide
helium
nitrogen
oxygen
neon
melting point / °C
- 189
-270
- 210
- 219
boiling point / °C
- 186
sublimes at -78( solid to
)
gas
- 249
- 269
- 196
- 183
- 246

(a) Which substances are liquids at -187 °C?