3. The core that Richard Oldem had discovered turned out to be the Earth's
I

The first layer is the crust, a skin of rock covering the planet. The core that Lehman had found was the Earth's inner core. The core that Richard Oldem had discovered turned out to be the Earth's outer core.

Explanation:

the answer is; comparing the frequency of collisions with and without the device

this makes the anti-collision system an independent variable and the collisions a dependent variable. if there are fewer collisions with an anti-collision system that without, then it can be stated that the system is a success. essentially, collisions under an anti-collision system are compared with the frequency of collisions by cars with the human drivers.