Why do farmers find it difficult to raise crops in the northeast?

Several billion years ago which gas was the least prevailant in the atmosphere

Which of the following factors would not contribute to allopatric speciation? a) a population becomes geographically isolated from the parent population.b) the separated population is small, and genetic drift occurs.c) the isolated population is exposed to different selection pressures than the ancestral population.d) different mutations begin to distinguish the gene pools of the separated populations.e) gene flow between the two populations is extensive.

How are viruses different from eukaryotic cells?