The fossil record shows scientists that A. all species from Earth's history became extinct. B. organism diversity has been the same throughout Earth's history. C. modern species are the same as those from Earth's earliest history. D. the diversity of life on Earth has changed over time.

D. the diversity of life on Earth has changed over time.

Explanation:

x = sqrt(45)

Step-by-step explanation:

We can use the Pythagorean theorem since this is a right triangle

a^2 + b^2 = c^2

where a and b are the legs and c is the hypotenuse

2^2 + x^2 = 7^2

4+x^2 = 49

Subtract 4 from each side

4-4+x^2 = 49-x

x^2 = 45

Take the square root of each side

sqrt(x^2) = sqrt(45)

x = sqrt(45)