Simple statement: conveys a single idea
Compound statement: conveys two or more ideas
Answer:
1. If the plane is late, I'll miss my connection: Compound
As it has the word if, then it is a Conditional type.
2. It snowed last winter: Simple
3. The store is open or the owner is on vacation: Compound
• As it has the word ,or,, ,then it is ,Disjunction ,type.