B. The U.S stock market crash and Franklin D Roosevelt’s policies
Answer:
an idea that can't be proven but can explain some phenomena
Explanation:
sorry if I am wrong
I believe it’s circulatory system.
Answer:The optical microscope, often referred to as the light microscope, is a type of microscope that commonly uses visible light and a system of lenses to magnify images of small objects.
Explanation:Optical microscopes are the oldest design of microscope and were possibly invented in their present compound form in the 17th century.
Students should always wear goggles in the laboratory
