Read the paragraph below and choose the best option indicating what 'their refers to . Due to the decreasing amount of fossil fuels, and the increase in their price for governments and consumers, Charles Darwin's express WOuld perfectly suit the ongoing competition for the remaining fossil fuels by powerful and wealthier countries. Many leading economically and politically in weaker and poorer economies for their rich ground on fossil fuels. But what are fossil fuels?

1)powerful and wealthier countries

2)many leading countries

3)weaker and poorer economies

4)fossil fuels

Spammer here

answer: i would say he was very determined and persistent in overcoming obstacles.

explanation:   "the magician of menlo park" as he was called, liked to tell an incident that happened when he was 8 years old and came back home crying after attending school for three months because his teacher called him "sterile and unproductive". from nowadays perspective, we can say that thomas alva edison was one of the most persistent and determined man that has ever existed. when edison was 14, he contracted scarlet fever. the effect of the fever, as well as a blow to the head by an angry train conductor, caused edison to become completely deaf in his left ear, and 80-percent deaf in the other. so as you can see he had to struggle to not so many minor issues but he always succeeded.