A scientist tries to mate the two similar-looking fruit flies Drosophila melanogaster and Drosophila simulans. But he finds that
they are unable to produce viable offspring.What kind of evolutionary barrier could this be? A) Chromosomal
B) Postzygotic
C) Physical
ANSWER QUESTION SAP
If the offspring resulting from the crossing of the two fly species is not viable, it means that although the hybrids were produced, they do not have the biological characteristics to survive and therefore, that there is a postzygotic barrier (it occurs after the zygote has formed).
A postzygotic barrier is condition that prevents hybrids from surviving (dying) or reproducing (infertility).
When these viruses insert their genome into the host cell, they usually have a reverse transcriptase enzyme that converts the RNA to DNA before it is integrated into the host genome. This is before the host cell machinery is hijacked to replicate the viruses components.
If you have trouble telling the difference between cohesion and adhesion, remember that an adhesive is glue, water is essentially "gluing" itself to another surface.
