Why could tropical rain forests be called the "medicine chest of the Earth?

Which type of neuroglia is found outside of the brain?

What organ is the first to receive nutrients that have been absorbed from the digestive tract?

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.