instruction:
In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
question:
Friction occurs when _ objects rub together.
answer:
two


question:
Optical isomers differ in the arrangement of _ groups around a chiral carbon.
answer:
four


question:
Buttercups can grow up to _ to three feet tall and can be about an inch across.
answer:

one