Question

Which is a process that leads to speciation?

A.
Populations become isolated over a long period of time.

B.
Spontaneous generation allows for behavioral adaptations.

C.
Natural selection allows for adaptations to occur regardless of the environment.

D.
Spontaneous generation allows for structural adaptations.

Answer 1

http://agron-www.agron.iastate.edu/~weeds/AG517/Content/ChangeCommun/speciation.html

Answer 2

"Process of Speciation
The process of speciation is a 2 stage process in which reproductive isolating mechanisms (RIM's) arise between groups of populations.
Stage 1

gene flow is interupted between 2 populations
absence of gene flow allows 2 populations to become genetically differentiated as a consequence of their adaptation to different local conditions (genetic drift also can act here too)
as populations differentiate, RIMs appear because different gene pools are not mutually coadapted
reproductive isolation appears primarily in the form of postzygotic RIMs: hybrid failure
these early RIMs are a byproduct of genetic differentiation, not directly promoted by natural selection yet
Stage 2
completion of genetic isolation
reproductive isolation develops mostly in the forms of prezygotic RIMs
development of prezygotic RIMs is directly promoted by natural selection: alleles favoring intraspecific fertility"