<s>
It_PPH1 has_VHZ been_VBN argued_VVN that_CST species_NN survival_NN1 is_VBZ the_AT most_RGT pertinent_JJ question_NN1 facing_VVG humankind_NN1 ._. 
</s>
<s>
The_AT truth_NN1 of_IO such_DA an_AT1 argument_NN1 is_VBZ highly_RR debatable_JJ ,_, but_CCB it_PPH1 is_VBZ no_RR21 doubt_RR22 an_AT1 important_JJ question_NN1 regardless_RR ._. 
</s>
<s>
Various_JJ obstacles_NN2 stand_VV0 in_II the_AT way_NN1 of_IO human_JJ survival_NN1 ,_, notably_RR limited_JJ resource_NN1 availability_NN1 ,_, illnesses_NN2 ,_, pollution_NN1 ,_, and_CC conflicting_JJ ideologies_NN2 between_II civilizations_NN2 ._. 
</s>
<s>
Both_RR pessimistic_JJ and_CC optimistic_JJ theories_NN2 have_VH0 been_VBN developed_VVN regarding_II humanity_NN1 's_GE ultimate_JJ fate_NN1 ._. 
</s>
<s>
Pessimists_NN2 such_II21 as_II22 Neo-Malthusians_NN2 contend_VV0 that_CST a_AT1 growing_JJ population_NN1 ,_, complemented_VVN by_II depleting_VVG resources_NN2 ,_, will_VM eventually_RR lead_VVI to_TO humankind'_VVI s_ZZ1 peril_NN1 ._. 
</s>
<s>
Such_DA a_AT1 process_NN1 began_VVD with_IW the_AT so-called_JJ green_JJ revolution_NN1 in_II agriculture_NN1 ,_, which_DDQ created_VVD a_AT1 foundation_NN1 for_IF a_AT1 large_JJ population_NN1 ._. 
</s>
<s>
As_CSA competition_NN1 for_IF resources_NN2 increases_VVZ ,_, people_NN more_RGR often_RR act_VV0 in_II31 accord_II32 with_II33 their_APPGE own_DA needs_NN2 ,_, as_II31 opposed_II32 to_II33 the_AT needs_NN2 of_IO society_NN1 ._. 
</s>
<s>
This_DD1 "_" tragedy_NN1 of_IO the_AT commons_NN2 "_" pollutes_VVZ the_AT environment_NN1 and_CC depletes_VVZ resources_NN2 to_II the_AT point_NN1 where_RRQ humanity_NN1 can_VM no_RR21 longer_RR22 sustain_VVI itself_PPX1 ._. 
</s>
<s>
Optimists_NN2 claim_VV0 that_CST human_JJ ingenuity_NN1 can_VM solve_VVI all_DB problems_NN2 created_VVN by_II a_AT1 large_JJ population_NN1 ._. 
</s>
<s>
They_PPHS2 contend_VV0 that_DD1 population_NN1 growth_NN1 has_VHZ provided_VVN for_IF ,_, rather_II21 than_II22 been_VBN adverse_JJ to_TO ,_, sustained_JJ development_NN1 ._. 
</s>
<s>
They_PPHS2 argue_VV0 that_DD1 life_NN1 expectancy_NN1 and_CC standard_NN1 of_IO living_NN1 have_VH0 steadily_RR increased_VVN ,_, while_CS infant_NN1 mortality_NN1 has_VHZ decreased_VVN ._. 
</s>
<s>
While_CS certain_JJ pessimistic_JJ (_( and_CC some_DD optimistic_JJ )_) theories_NN2 have_VH0 been_VBN discredited_VVN ,_, some_DD still_RR make_VV0 strong_JJ arguments_NN2 ._. 
</s>
<s>
Only_JJ time_NNT1 will_VM tell_VVI which_DDQ is_VBZ correct_JJ ._. 
</s>
