instruction:
Given a scientific question, generate a correct answer to it.
question:
Carboxylic acids have an acidic hydrogen atom, but esters do not. what do esters have in place of an acidic hydrogen atom?
answer:
hydrocarbon group

question:
The sun and all objects held by it's gravity make up the?
answer:
solar system

question:
Generators convert mechanical energy to which kind?
answer:
electrical