"Eosc114(earth and ocean science) ubc:

1. Which of the following about the Ordovician biosphere is TRUE?

A) Dinosaurs were a common component of the oceanic ecosystem

B) The creatures present in the Ordovician had evolved from forms that existed in the Cretaceous

C) Most of the creatures became extinct (either directly or indirectly) due to the poisoning of the oceans by acid rain

D) Ice would have a major role to play in causing mass extinction in the biosphere

E) The question does not make sense. There was no biosphere during the Ordovician as life had yet to evolve

2. Which of the following statements is TRUE about the Cretaceous-Tertiary (K/T) extinction event? 

A) The event was geologically instantaneous. Starting with the impact it probably took less than a year to cause a 50% drop in the biosphere 
B) All dinosaurs and their close relatives would be driven into extinction due to them being far too specialized 
C) In sediment cores covering the K/T boundary, iridium is always present below the tsunami layer 
D) “Burning” nitrogen in the atmosphere may have generated acid rain 
E) The accelerated formation of Pangea was causing many environmental problems

3. “Nemesis” has been used to explain which of the following? 

A) Gravity
B) Raup-Sepkoski periodicity 
C) The existence of the Oort cloud outside the orbit of Pluto 
D) Gravitational kicks from the densest part of the galactic plane 
E) The existence of black holes"