A student is implementing an investigation of physical properties using samples of metals, nonmetals, and metalloids. She is a battery, wires, and the bulb to test if each of the samples were complete the circuit causing the bulb to light. Next, she shine a bright light on each of the samples which physical properties is a student investigating?

Penelope studies how the structure and function of the nervous system is related to behavior. she is a psychologist

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.

What are 3 reasons that natural selection occurs