Which one of the following is based on the heating effect of current 1. Geyser
2. Hair dryer
3. Immersion rod
4. All of these

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

it was spontaneous.

"ain't i a woman? " is the name given to a speech, delivered extemporaneously, by sojourner truth, (1797–1883), born into slavery in new york state.sojourner truth' delivered her famous speech "ain't i a woman? " (which did not have a title at that moment) was given without any previous preparation. her dissertation took place at the women's convention in akron, ohio, in 1851.