To enter and exit a cell, molecules often travel across the membrane via transmembrane proteins. Some of these proteins are active, some are passive. From the following transmembrane proteins, which one is active?

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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.

In this picture, groups of pigment that capture light energy are located on the