<span>There are three types of hybrid reproductive barriers. The one described is called hybrid breakdown. In hybrid breakdown as the hybrid organisms continue to reproduce each sequential generation becomes less viable, healthy and loses it's ability to reproduce. The other two hybrid reproductive barriers are hybrid sterility and hybrid inviability. Hybrid sterility results in healthy organisms that can not reproduce at all since thy are sterile. Hybrid inviability results in organisms that are not strong enough to survive and often die while juveniles.</span>
The surface of the early Earth is often described as hellish by scientists. The high temperature is primarily attributed to the high levels of carbon dioxide in the atmosphere and the molten rock on the surface of the planet. However, these two aren't the only factors in play.
Another factor that contributed to the extremely high temperature of the early earth is radioactivity. Radioactive decay of the isotopes found underground plus the left over heat from the formation of our planet produced high levels of radiogenic heat.
There's also the kinetic energy from falling asteroids and meteorites. Massive amounts of energy in the form of heat and sound is produced when asteroids and meteorites hit the Earth. Also, the pressure waves that travel radially outwards the center of the impact is similar to the impact of an atom bomb. As such, dust particles envelop the atmosphere, trapping the heat from the impact.
The last factor is the gravitational contraction, it contributed to the hellish temperature of primordial Earth because the energy generated from such event is enough to trigger hydrogen fusion.
I think that the answer is D. The cell employs the G2 checkpoint to check for DNA damage and completeness of DNA replication. This is done to ensure that cell division runs smoothly which means that healthy daughter cells, with complete and undamaged DNA, will be produced. At this point, all necessary repairs are applied.
Answer:
There was a time when I was in high school and I had a Math test. I did all the tasks in the test and was sure I answered everything correctly. However, just before I was about to submit the test, I saw that I forgot to add the minus sign (-) in one of the results. I quickly corrected my mistake and successfully submitted my test. In the end, I got an A as I really answered everything correctly.
