Covalent bond because a covalent bond is when it only shares electrons and it doesn't give or lose.
Answer:
A. Hypothesis
Explanation:
A hypothesis is a well-tested, scientifically supported statement that explains how something works.
Answer:
B. Meteorites struck the region that Mexico now occupies
Explanation:
The meteorite or comet that struck in the area where Mexico is located in the present is not part of the consequences of the extinctions event. The reason why it is not part of the consequences is that it is the factor that caused the consequences, so it can not be both the thing that caused something and also the consequence of it. This meteorite or comet managed to create such a huge explosion, that it managed to wipe out pretty much all large and medium sized land dwelling animals. And that was not caused only by the explosion itself, but also because it drastically changed the climate with the huge amounts of ashes and dust released into the atmosphere, as well as the triggering of the volcanoes around the world. This mass extinction though opened up the gates for the evolution of the mammals which soon became the dominant animals on the planet.