Rock layers right at the K-Pg boundary have enriched concentrations of the element iridium. This is significant for understanding the mass extinction that happened at the time, because ________
A) iridium is toxic to life and could have killed off many species
B) iridium is very rare in the Earth's crust but relatively common in meteorites
C) iridium forms under conditions of extreme shock and heat
D) iridium would have caused an episode of severe acid rain
E) iridium-rich dust is particularly effective at blocking incoming solar radiation
B
You might also like to view...
Four of the five answers listed below are haploid cells. Select the exception
a. zygote b. spore c. egg d. sperm e. gamete
Sense receptors for "taste" are located in all of the following EXCEPT
a. on the tongue. b. on the roof of the mouth. c. in the throat. d. on the palate. e. on the tonsils.
Class Betaproteobacteria includes all but which of the following genera?
A. Neisseria B. Bordetella C. Lepothrix D. Campylobacter
The organism with the highest fitness is
A. an animal that lives 2 years and produces 10 offspring per year. B. an animal that lives 10 years and produces 2 offspring per year. C. an animal that lives one year and produces 10 offspring total. D. an animal that lives 10 years and produces 10 offspring per year. E. an animal that lives 100 years and produces 10 offspring total.