Based on context clues, what is the best definition of the word "expendable"?

What noticeable trend from this graph might be used to make a conclusion?

10111213141516lactic acid fermentation differs from ethyl alcohol fermentation in thato in ethyl alcohol fermentation co2 is also producedlactic acid fermentation can occur in all living thingsethyl alcohol fermentation can only occur in plantsonly lactic acid fermentation can produce more atp

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.