Oil and natural gas eventually reached layers of rock through which they could not pass called . Multiple choice question.

A)
deep rock

B)
permeable rock

C)
impermeable rock

D)
cement

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.

answer; i believe the correct answer to the above question is ( friction)