In most cases,the effects of population increase,or of environmental resistance,are not felt instantly.

When a large number of species is lost over a relatively short time span,such as a few centuries,this situation is described as: 

A)  an eco-catastrophe 
B)  an extinction spasm 
C)  a major death sequence 
D)  an extinction sink

Which is often a limiting a limiting factor on terrestrial ecosystems? 

A)  dissolved oxygen 
B)  dissolved hydrogen 
C)  precipitation 
D)  salinity

The infrared portion of the electromagnetic spectrum helps planetary scientists measure surface:

A) composition and temperature
B) temperature and elevation
C) age and composition
D) age and elevation