During an evening hike, you see a shooting star just like the one pictured here.

In which layer of the atmosphere does this shooting star occur?
edgunuity

troposphere

stratosphere

mesosphere

thermosphere

Which of the following particles always has a positive charge? a. electronb. neutron c. proton d. ion

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 general, characteristics that an organism survive and reproduce become more common in a population over time. what mechanism of evolution cause this change?