Elon Musk: Private Spaceflight Pioneer. Credible?

The graph below shows how the price of wheat varies with the demand quantity. suppose that lower production costs increases the supply of wheat, such that more wheat is supplied at each price level. the new equilibrium price (after the increase in supply) is

Potentially, a large spill can be: a) an environmental threat, if it gets into drains b) a dangerous fire hazard c) harmful to individuals d) all of the above

What greek scientist created a screw to move water for irrigation?