1. What was the major discovery or invention?

Well here's a few ( depends what you're talking about)

Explanation:

the discovery of fire

the invention of farming (planting seeds, then caring for and harvesting the crops)

the invention of the wheel

the invention of sails and sailing ships

the invention of gunpowder

the invention of writing

the invention of paper

the invention of printing

the discovery of the circulation of blood (how the heart pumps blood throughout the body)

the invention of the microscope and telescope

the discovery of microorganisms

the discovery that earth circles the sun

the discovery of gravity

the discovery of electricity and ways to control it

the invention of steam ships

the invention of the gasoline engine and motor vehicles (cars, trucks, etc.)

the invention of the telephone

the invention of the radio

the discovery of penicillin and other antibiotics

the invention of the computer and then the Internet

the atmospheric gas that forms a mild acid when dissolved in water is called carbon dioxide. the correct answer is a. 2.) chemical weathering would cause an inscription on a marble headstone to become harder and harder to read over time.

the most common type of reef is the fringing reef. this type of reef grows seaward directly from the shore. they form borders along the shoreline and surrounding islands.