question:
Sometimes what were widely considered to be separate species produced fertile hybrid offspring freely, and in other cases what were considered to be mere varieties of the same species could only be crossed with difficulty.
Why would hybrids have characteristics that keep them from being fertile?

answer: no

question:
Unlike other domestic species which were primarily selected for production-related traits, dogs were initially selected for their behaviors.
Instead of genetic traits for production, dogs are bred for what?

answer: yes

question:
A Master's degree requires two years of study following the attainment of a bachelor's degree.
How long does it typically take to earn a Master's degree?

answer: yes

question:
The first two columns (32 positions) were reserved for control characters.:220, 2368,9)
How many positions are in the first two columns?

answer:
yes