What subjects did Percy Spencer teach himself?

During this time he taught himself a number of scientific subjects, including calculus, chemistry, metallurgy, physics, and trigonometry.

Explanation:

when a country suffers, for example, a drought period, the market product is affected for a low offer, in this case, potatoes; the government has to tax to the households, which have to give more money for the potatoes which they consume, that situation make them consume substitute goods even through loans, it could increase the financial market movement and the inflationary phenomena, the business has to increase salaries in order to the employees could buy a more expensive food (potatoes) and in order to inflation tha business had to buy expensive supplies in the factor market, while the rest of the world have to gain more money to consume the same amount of potatoes.

a. theta waves. this is because the person is in a light sleep which means the brain waves would show these kind of waves.