Which of the following is NOT believed by scientists to have been present in the early earths atmosphere? a. Ammonia
b. Free oxygen
c. Methane gas
d. Water vapor

What pattern of migration do whales follow?

Which of the following produces carbon dioxide? a. plants b. animals c. decomposers d. all of the above

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.