Why are there black holes on the moon

caused by asteroids hitting it

Explanation:

I don't think it is a black hole, thinks it's called a crater/pit

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 that the correct answer is (lung);