What two countries have nearly 50% of global coal reserves? a. united states and canada b. united states and russia c. brazil and russia d. brazil and canada

the answer is USA and Russia

Ans: B) United States and Russia

Energy sources can be broadly classified into two categories: Renewable and non-renewable sources.

Renewable sources are those that can be naturally replenished like, solar energy, wind, hydrothermal etc

In contrast, non-renewable sources of energy are a finite resources and cannot be replenished. Fossil fuels like coal, oil, gas are all non-renewable sources. Coal is the most widely used source of energy with the United States and Russia being the two countries that have nearly 50% of the global coal reserves.

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.