Since invasive species did not co-evolve with the other species in the ecosystem where they were introduced . a. they can unbalance the ecosystem b. they are considered a serious environmental problem c. they lack natural predators to help control their population d. all of the above

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.

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.