"This is a high-speed roller coaster ride. It is not recommended for those with a heart condition, back problems, or pregnant mothers."
- Error: The list of items in the second sentence does not have a parallel structure.
Correction:
"This is a high-speed roller coaster ride. It is not recommended for pregnant women or for those with heart conditions or back problems."
Revised:
"This high-speed roller coaster is not recommended for pregnant women or for those with heart conditions or back problems."
