Final answer:
The limited topic of the sentence is 'Burmese pythons,' and the separation of Python curtus, Python brongersmai, and Python breitensteini into distinct species due to geographic isolation is an example of allopatric speciation.
Step-by-step explanation:
The limited topic of the following topic sentence "Burmese pythons can make surprisingly affectionate pets." is Burmese pythons. It is because the sentence focuses specifically on the characteristics of Burmese pythons as pets, rather than pets in general or the broader concept of pets being affectionate.
Regarding the separate information provided about the species Python curtus, Python brongersmai, and Python breitensteini, their initial classification as one species and later distinction into three separate species based on different geographic locations is an example of allopatric speciation. This is when new species are formed in geographic isolation from one another.