The correct answer is D. The need for coinage of silver money
Answer: Percy Spencer
Percy Spencer, was an American engineer. He was the inventor of the microwave oven in 1945, serving the Raytheon company.
The calorific effect of microwaves was discovered by the American Percy Spencer. While experimenting with radars and microwaves, he noticed that the candy bar in his pocket had almost melted. He sought the explanation of this fact, the grain of corn under the effect of these waves and within seconds they were transformed into popcorn. The microwaves had agitated the water molecules contained in the corn kernels, rubbed them against each other, and warmed them.
B and C I’m pretty sure it was also because of a problem with the O-rings on the shuttle
What Is a Roth IRA? A Roth IRA is a special retirement account that you fund with post-tax income (you can't deduct your contributions on your income taxes). Once you have done this, all future withdrawals that follow Roth IRA regulations are tax free
