Answer:
b. inner core
Step-by-step explanation:
To solve this problem let's start by listing the information given. This will help us find which option best fits the characteristics provided to find the correct answer.
characteristics of mystery layer:
i. it is solid and extremely hot
ii. it is the innermost layer of the Earth
iii. it is around 800 miles thick
Now let's go through each option to determine which best matches the characteristics.
option a
outer core
The first characteristic of the mystery layer is 'it is solid and extremely hot.' The outer core of the earth, however, is a fluid layer. Therefore, this option cannot be correct.
option b
inner core
The inner core is a solid 'ball' and is about 10,800°F. It is also the inner, or last layer, of the earth and is around 800 miles thick. Therefore, it matches all characteristics of the mystery layer so, this must be the correct answer. If you would like to be sure, I also reviewed the last two options below.
option c
crust
Because the crust is the outermost layer of the planet, it does not match the second characteristic of the mystery layer. Therefore, this cannot be the correct answer to the question.
option d
mantle
Although the mantle does match the first characteristic, it does not match the second characteristic, which requires the layer to be the innermost layer of the earth. The mantle is one of the outer layers of the earth.
Now that all options are reviewed, we have determined the best solution to the problem. The correct answer to this question is b. inner core.