drought and flooding high tides and low tides clear skies and cloudy skies hot weather and cool weather
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Which of these natural events occurs at time intervals that are the most regular?
Possibilities:
- drought and flooding
- high tides and low tides
- clear skies and cloudy skies
- hot weather and cool weather

high tides and low tides